File rxvt-unicode-post-9.22.patch of Package rxvt-unicode
--- rxvt-unicode/autogen.sh
+++ rxvt-unicode/autogen.sh
@@ -5,7 +5,19 @@
**
** libev/ directory is missing
**
-** you need a checkout of libev (http://software.schmorp.de/pkg/libev)
+** you need a checkout of libev (http://software.schmorp.de/pkg/libev.html)
+** in the top-level build directory.
+**
+EOF
+ exit 1
+fi
+
+if ! [ -e libptytty/ptytty.m4 ]; then
+ cat <<EOF
+**
+** libptytty/ directory is missing
+**
+** you need a checkout of libptytty (http://software.schmorp.de/pkg/libptytty.html)
** in the top-level build directory.
**
EOF
--- rxvt-unicode/Changes
+++ rxvt-unicode/Changes
@@ -37,6 +37,32 @@
TODO: c&c perl socket via daemon-ext mechanism
TODO: simplify extension metainfo cache, cache on disk
TODO: URxvt::Ext::Name installs urxvt ext name and provides pod/manpage for URxvt::Ext::Name
+TODO: üpixel droppins idenrasm,ll,scrollup
+TODO: cuu/cud and probably others default to 1 when arg is 0, not just missing, in xterm/vt102, but not in rxvt
+TODO: implement xterms nih 1006 mouse mode because the fud campaign against urxvt's 1015 mode works.
+
+TODO: fix ESC G reply forever, or simply completely disable it?
+ - improved security: rob nation's (obsolete) graphics mode queries
+ no longer reply with linefeed in secure/default mode.
+ - ISO 8613-3 direct colour SGR sequences (patch by Fengguang Wu).
+ - xterm focus reporting mode (patch by Daniel Hahler).
+ - in some window managers, if smart resize was enabled, urxvt
+ erroneously moved the window on font change - awesome bug
+ #532, arch linux bug ##34807 (patch by Uli Schlachter).
+ - fix urxvtd crash when using a background expression.
+ - properly restore colors when using fading and reverse video
+ is enabled while urxvt is focused and then disabled while it
+ is not focused, or vice versa (patch by Daniel Hahler).
+ - fix high memory usage when an extension repeatedly hides and
+ shows an overlay (reported by Marcel Lautenbach).
+ - the old bg image resources are now provided by the background
+ extension, and perl is thus required for bg image support. No
+ configuration change is needed: urxvt autoloads the background
+ ext if any bg image resource/option is present. The old bg image
+ resources are also now deprecated; users are encouraged to
+ switch to the new bg image interface (see man urxvt-background).
+ - expose priv_modes member and constants to perl extensions
+ (patch by Rastislav Barlik).
9.22 Sat Jan 23 21:07:33 CET 2016
- NOTICE: this release updates terminfo.
--- rxvt-unicode/doc/podtbl
+++ rxvt-unicode/doc/podtbl
@@ -81,6 +81,10 @@
# pod::xhtml fails on begin/end blocks
# print $fh "=begin xhtml\n\n";
+ print $fh "=for xhtml <table>";
+ print $fh map "<tr><td>" . +(join "</td><td>", htmlfcodes @$_) . "</td></tr>", @$table;
+ print $fh "</table>\n\n";
+
print $fh "=for html <table>";
print $fh map "<tr><td>" . +(join "</td><td>", htmlfcodes @$_) . "</td></tr>", @$table;
print $fh "</table>\n\n";
--- rxvt-unicode/doc/rxvt.1.pod
+++ rxvt-unicode/doc/rxvt.1.pod
@@ -1081,10 +1081,25 @@
(modifiers-)key
-Where I<modifiers> can be any combination of B<ISOLevel3>, B<AppKeypad>,
-B<Control>, B<NumLock>, B<Shift>, B<Meta>, B<Lock>, B<Mod1>, B<Mod2>,
-B<Mod3>, B<Mod4>, B<Mod5>, and the abbreviated B<I>, B<K>, B<C>, B<N>,
-B<S>, B<M>, B<A>, B<L>, B<1>, B<2>, B<3>, B<4>, B<5>.
+Where I<modifiers> can be any combination of the following full or
+abbreviated modifier names:
+
+=begin table
+
+ B<ISOLevel3> B<I>
+ B<AppKeypad> B<K>
+ B<Control> B<C>
+ B<NumLock> B<N>
+ B<Shift> B<S>
+ B<Meta> B<M> B<A>
+ B<Lock> B<L>
+ B<Mod1> B<1>
+ B<Mod2> B<2>
+ B<Mod3> B<3>
+ B<Mod4> B<4>
+ B<Mod5> B<5>
+
+=end table
The B<NumLock>, B<Meta> and B<ISOLevel3> modifiers are usually aliased to
whatever modifier the NumLock key, Meta/Alt keys or ISO Level3 Shift/AltGr
@@ -1325,120 +1340,6 @@
=back
-=head1 BACKGROUND IMAGE OPTIONS AND RESOURCES
-
-=over 4
-
-=item B<-pixmap> I<file[;oplist]>
-
-=item B<backgroundPixmap:> I<file[;oplist]>
-
-Compile I<pixbuf>: Use the specified image file as the window's
-background and also optionally specify a colon separated list of
-operations to modify it. Note that you may need to quote the C<;>
-character when using the command line option, as C<;> is usually a
-metacharacter in shells. Supported operations are:
-
-=over 4
-
-=item B<WxH+X+Y>
-
-sets scale and position. B<"W" / "H"> specify the horizontal/vertical
-scale (percent), and B<"X" / "Y"> locate the image centre (percent). A
-scale of 0 disables scaling.
-
-=item B<op=tile>
-
-enables tiling
-
-=item B<op=keep-aspect>
-
-maintain the image aspect ratio when scaling
-
-=item B<op=root-align>
-
-use the position of the terminal window relative to the root window as
-the image offset, simulating a root window background
-
-=back
-
-The default scale and position setting is C<100x100+50+50>.
-Alternatively, a predefined set of templates can be used to achieve
-the most common setups:
-
-=over 4
-
-=item B<style=tiled>
-
-the image is tiled with no scaling. Equivalent to 0x0+0+0:op=tile
-
-=item B<style=aspect-stretched>
-
-the image is scaled to fill the whole window maintaining the aspect
-ratio and centered. Equivalent to 100x100+50+50:op=keep-aspect
-
-=item B<style=stretched>
-
-the image is scaled to fill the whole window. Equivalent to 100x100
-
-=item B<style=centered>
-
-the image is centered with no scaling. Equivalent to 0x0+50+50
-
-=item B<style=root-tiled>
-
-the image is tiled with no scaling and using 'root' positioning.
-Equivalent to 0x0:op=tile:op=root-align
-
-=back
-
-If multiple templates are specified the last one wins. Note that a
-template overrides all the scale, position and operations settings.
-
-If used in conjunction with pseudo-transparency, the specified pixmap
-will be blended over the transparent background using alpha-blending.
-
-=item B<-tr>|B<+tr>
-
-=item B<transparent:> I<boolean>
-
-Turn on/off pseudo-transparency by using the root pixmap as background.
-
-B<-ip> (B<inheritPixmap>) is still accepted as an obsolete alias but
-will be removed in future versions.
-
-=item B<-tint> I<colour>
-
-=item B<tintColor:> I<colour>
-
-Tint the transparent background with the given colour. Note that a
-black tint yields a completely black image while a white tint yields
-the image unchanged.
-
-=item B<-sh> I<number>
-
-=item B<shading:> I<number>
-
-Darken (0 .. 99) or lighten (101 .. 200) the transparent background.
-A value of 100 means no shading.
-
-=item B<-blr> I<HxV>
-
-=item B<blurRadius:> I<HxV>
-
-Apply gaussian blur with the specified radius to the transparent
-background. If a single number is specified, the vertical and
-horizontal radii are considered to be the same. Setting one of the
-radii to 1 and the other to a large number creates interesting effects
-on some backgrounds. The maximum radius value is 128. An horizontal or
-vertical radius of 0 disables blurring.
-
-=item B<path:> I<path>
-
-Specify the colon-delimited search path for finding background image files.
-
-=back
-
=head1 THE SCROLLBAR
Lines of text that scroll off the top of the B<@@RXVT_NAME@@> window
@@ -1598,6 +1499,15 @@
240 in 256 colour mode) colours arranged in an 4x4x4 (or 6x6x6) colour RGB
cube plus a 8 (24) colour greyscale ramp.
+B<@@RXVT_NAME@@> supports direct 24-bit fg/bg RGB colour escapes
+C< ESC [ 38 ; 2 ; R ; G ; Bm > / C< ESC [ 48 ; 2; R ; G ; Bm >. However the
+number of 24-bit colours that can be used is limited: an internal 7x7x5 (256
+colour mode) or 6x6x4 (88 colour mode) colour cube is used to index into the
+24-bit colour space. When indexing collisions happen, the nearest old colour in
+the cube will be adapted to the new 24-bit RGB colour. That means one cannot
+use many similar 24-bit colours. It's typically not a problem in common
+scenarios.
+
Here is a list of the ANSI colours with their names.
=begin table
--- rxvt-unicode/doc/rxvt.7.pod
+++ rxvt-unicode/doc/rxvt.7.pod
@@ -1605,6 +1605,8 @@
B<< C<Pm = 36 / 46> >> fg/bg Cyan
B<< C<Pm = 37 / 47> >> fg/bg White
B<< C<Pm = 38;5 / 48;5> >> set fg/bg to colour #m (ISO 8613-6)
+ B<< C<Pm = 38;2;R;G;B> >> set fg to 24-bit colour #RGB (ISO 8613-3)
+ B<< C<Pm = 48;2;R;G;B> >> set bg to 24-bit colour #RGB (ISO 8613-3)
B<< C<Pm = 39 / 49> >> fg/bg Default
B<< C<Pm = 90 / 100> >> fg/bg Bright Black
B<< C<Pm = 91 / 101> >> fg/bg Bright Red
@@ -1934,12 +1936,12 @@
=end table
-=item B<< C<Pm = 1004> >> (X11 XTerm focus in/focus out events) I<unimplemented>
+=item B<< C<Pm = 1004> >> (X11 XTerm focus in/focus out events)
=begin table
B<< C<h> >> Send Mouse focus in/focus out events.
- B<< C<l> >> Don'T send focus events.
+ B<< C<l> >> Don't send focus events.
=end table
@@ -1948,7 +1950,7 @@
Try to avoid this mode, it doesn't work sensibly in non-UTF-8 locales. Use
mode C<1015> instead.
-Unlike XTerm, coordinates larger than 2015) will work fine.
+Unlike XTerm, coordinates larger than 2015 will work fine.
=begin table
@@ -2089,7 +2091,6 @@
B<< C<Ps = 13> >> Change colour of mouse foreground to B<< C<Pt> >>
B<< C<Ps = 17> >> Change background colour of highlight characters to B<< C<Pt> >>
B<< C<Ps = 19> >> Change foreground colour of highlight characters to B<< C<Pt> >>
- B<< C<Ps = 20> >> Change background pixmap parameters (see section BACKGROUND IMAGE) (Compile pixbuf).
B<< C<Ps = 39> >> Change default foreground colour to B<< C<Pt> >>. [deprecated, use 10]
B<< C<Ps = 46> >> Change Log File to B<< C<Pt> >> I<unimplemented>
B<< C<Ps = 49> >> Change default background colour to B<< C<Pt> >>. [deprecated, use 11]
@@ -2098,7 +2099,6 @@
B<< C<Ps = 701> >> Change current locale to B<< C<Pt> >>, or, if B<< C<Pt> >> is B<< C<?> >>, return the current locale (Compile frills).
B<< C<Ps = 702> >> Request version if B<< C<Pt> >> is B<< C<?> >>, returning C<rxvt-unicode>, the resource name, the major and minor version numbers, e.g. C<ESC ] 702 ; rxvt-unicode ; urxvt ; 7 ; 4 ST>.
B<< C<Ps = 704> >> Change colour of italic characters to B<< C<Pt> >>
- B<< C<Ps = 705> >> Change background pixmap tint colour to B<< C<Pt> >> (Compile transparency).
B<< C<Ps = 706> >> Change colour of bold characters to B<< C<Pt> >>
B<< C<Ps = 707> >> Change colour of underlined characters to B<< C<Pt> >>
B<< C<Ps = 708> >> Change colour of the border to B<< C<Pt> >>
@@ -2114,27 +2114,6 @@
=back
-=head1 BACKGROUND IMAGE
-
-For the BACKGROUND IMAGE XTerm escape sequence B<< C<ESC ] 20 ; Pt ST> >> the value
-of B<< C<Pt> >> can be one of the following commands:
-
-=over 4
-
-=item B<< C<?> >>
-
-display scale and position in the title
-
-=item B<< C<;WxH+X+Y> >>
-
-change scale and/or position
-
-=item B<< C<FILE;WxH+X+Y> >>
-
-change background image
-
-=back
-
X<Mouse>
=head1 Mouse Reporting
@@ -2469,6 +2448,7 @@
compile in built-in block graphics
skip builtin block graphics (-sbg)
separate highlight colour (-highlightColor, -highlightTextColor)
+ focus reporting mode (1004).
extended mouse reporting modes (1005 and 1015).
visual selection via -visual and -depth.
--- rxvt-unicode/libecb/Changes
+++ rxvt-unicode/libecb/Changes
@@ -0,0 +1,124 @@
+TODO:
+08:30:06 <b_jonas> I think it could be worth to add a macro that works like alignof or _Alignof on sane
+ compilers, and like __alignof on MS compilers that support it, see
+ http://msdn.microsoft.com/en-us/library/45t0s5f4.aspx
+08:30:24 <b_jonas> even if you can't support it on all the old compilers
+08:31:17 <b_jonas> I'd also like a macro for alignas, but sadly, that seems impossible in general, because
+ the MS compiler only has some half-attempt to do something similar but with different and
+ more broken semantics, see http://msdn.microsoft.com/en-us/library/83ythb65.aspx
+08:31:35 <b_jonas> but I wonder if some special case could still be worth to support
+08:32:23 <b_jonas> probably not, because it would just account to making a union with a highly aligned type,
+ which is something I can do on any compiler portably
+
+TODO: #define ECB_IS_INTEGRAL(x) !((1 ? 1 : (x)) / 2)
+ #define ECB_IS_INTEGRAL(x) (sizeof ((x) + 1.0f) != sizeof((x) + 1ULL))
+
+TODO: __builtin_powi
+
+TODO: https://gustedt.wordpress.com/2010/06/08/detect-empty-macro-arguments/
+
+implement is_constant for c11: https://gustedt.wordpress.com/2013/08/22/testing-compile-time-constness-and-null-pointers-with-c11s-_generic/
+
+#ifdef _MSC_VER
+
+#include <stdlib.h>
+#define bswap_32(x) _byteswap_ulong(x)
+#define bswap_64(x) _byteswap_uint64(x)
+
+#elif defined(__APPLE__)
+
+// Mac OS X / Darwin features
+#include <libkern/OSByteOrder.h>
+#define bswap_32(x) OSSwapInt32(x)
+#define bswap_64(x) OSSwapInt64(x)
+
+#elif defined(__sun) || defined(sun)
+
+#include <sys/byteorder.h>
+#define bswap_32(x) BSWAP_32(x)
+#define bswap_64(x) BSWAP_64(x)
+
+#elif defined(__FreeBSD__)
+
+#include <sys/endian.h>
+#define bswap_32(x) bswap32(x)
+#define bswap_64(x) bswap64(x)
+
+#elif defined(__OpenBSD__)
+
+#include <sys/types.h>
+#define bswap_32(x) swap32(x)
+#define bswap_64(x) swap64(x)
+
+#elif defined(__NetBSD__)
+
+#include <sys/types.h>
+#include <machine/bswap.h>
+#if defined(__BSWAP_RENAME) && !defined(__bswap_32)
+#define bswap_32(x) bswap32(x)
+#define bswap_64(x) bswap64(x)
+#endif
+
+#else
+
+#include <byteswap.h>
+
+#endif
+
+ - apply ctz/ld patch for msc by Zsbán Ambrus.
+ - ECB_PTRSIZE erroneously was 8 on most 32bit systems (
+ found by Zsbán Ambrus).
+ - improved compiletime detection of endianness, also, allow
+ runtime detection to indicate other-than-big/little endianness.
+ - no memory barrier neded on arm < 6.
+
+0x00010005
+ - improve ecb_binary16_to_float.
+ - add ecb_float_to_binary16.
+ - add ecb_binary16_to_binary32 and ecb_binary32_to_binary16 pair.
+
+0x00010001
+ - add ecb_is_pot32/64.
+ - add intptr_t/uintptr_t.
+ - add ECB_PTRSIZE.
+ - more macros for C/C++ version checks.
+ - support C11 atomics for memory fences.
+ - support gcc-4.7 atomics for memory fences.
+ - support m68k, m88k and sh (patch by Miod Vallat).
+ - add ecb_binary16_to_float.
+
+TODO: ecb_restrict_array etc. http://ue.tst.eu/5093eafd713ec5fda776d8065070aa4c.txt
+TODO: ffs
+64 bit variants of everything
+TODO: examples from X for clz/ctz
+TODO: arithmetic right shift
+TODO: template/generic functions for x32/x64 and so on
+TODO: #define ecb_integer_multiples_of(n,d) ((char (*)[d])(n) - (char (*)[d])0)
+TODO: generalised shift
+TODO: #define ECB_FAST_UNALIGNED_ACCESS
+unsigned long gensh(unsigned long v, int x) {
+int a, b;
+ a = (v << x) & -(((unsigned int)x) < 32);
+ x = -x;
+ b = (v >> x) & -(((unsigned int)x) < 32);
+ return a|b;
+}
+
+TODO: export(=dllexport) & hidden
+TODO: flatten
+TODO: warning(msg)
+TODO: error(msg)
+TODO: leaf (uh), noclone (hmmm)
+TODO: nonnull, returns_nonnull
+TODO: nothrow
+TODO: used
+TODO: trap
+TODO: http://llvm.org/docs/doxygen/html/Compiler_8h_source.html
+
+TODO: read/write unaligned macros
+TODO: htonl and friends
+TODO: macro to convert from unsigned to signed "the natural way"
+TODO: ecb_static_assert, with message (just like boost), or somesuch, using array-declaration
+TODO: alignof
+
+
--- rxvt-unicode/libecb/ecb.h
+++ rxvt-unicode/libecb/ecb.h
@@ -0,0 +1,1011 @@
+/*
+ * libecb - http://software.schmorp.de/pkg/libecb
+ *
+ * Copyright (©) 2009-2015 Marc Alexander Lehmann <libecb@schmorp.de>
+ * Copyright (©) 2011 Emanuele Giaquinta
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef ECB_H
+#define ECB_H
+
+/* 16 bits major, 16 bits minor */
+#define ECB_VERSION 0x00010005
+
+#ifdef _WIN32
+ typedef signed char int8_t;
+ typedef unsigned char uint8_t;
+ typedef signed short int16_t;
+ typedef unsigned short uint16_t;
+ typedef signed int int32_t;
+ typedef unsigned int uint32_t;
+ #if __GNUC__
+ typedef signed long long int64_t;
+ typedef unsigned long long uint64_t;
+ #else /* _MSC_VER || __BORLANDC__ */
+ typedef signed __int64 int64_t;
+ typedef unsigned __int64 uint64_t;
+ #endif
+ #ifdef _WIN64
+ #define ECB_PTRSIZE 8
+ typedef uint64_t uintptr_t;
+ typedef int64_t intptr_t;
+ #else
+ #define ECB_PTRSIZE 4
+ typedef uint32_t uintptr_t;
+ typedef int32_t intptr_t;
+ #endif
+#else
+ #include <inttypes.h>
+ #if (defined INTPTR_MAX ? INTPTR_MAX : ULONG_MAX) > 0xffffffffU
+ #define ECB_PTRSIZE 8
+ #else
+ #define ECB_PTRSIZE 4
+ #endif
+#endif
+
+#define ECB_GCC_AMD64 (__amd64 || __amd64__ || __x86_64 || __x86_64__)
+#define ECB_MSVC_AMD64 (_M_AMD64 || _M_X64)
+
+/* work around x32 idiocy by defining proper macros */
+#if ECB_GCC_AMD64 || ECB_MSVC_AMD64
+ #if _ILP32
+ #define ECB_AMD64_X32 1
+ #else
+ #define ECB_AMD64 1
+ #endif
+#endif
+
+/* many compilers define _GNUC_ to some versions but then only implement
+ * what their idiot authors think are the "more important" extensions,
+ * causing enormous grief in return for some better fake benchmark numbers.
+ * or so.
+ * we try to detect these and simply assume they are not gcc - if they have
+ * an issue with that they should have done it right in the first place.
+ */
+#if !defined __GNUC_MINOR__ || defined __INTEL_COMPILER || defined __SUNPRO_C || defined __SUNPRO_CC || defined __llvm__ || defined __clang__
+ #define ECB_GCC_VERSION(major,minor) 0
+#else
+ #define ECB_GCC_VERSION(major,minor) (__GNUC__ > (major) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))
+#endif
+
+#define ECB_CLANG_VERSION(major,minor) (__clang_major__ > (major) || (__clang_major__ == (major) && __clang_minor__ >= (minor)))
+
+#if __clang__ && defined __has_builtin
+ #define ECB_CLANG_BUILTIN(x) __has_builtin (x)
+#else
+ #define ECB_CLANG_BUILTIN(x) 0
+#endif
+
+#if __clang__ && defined __has_extension
+ #define ECB_CLANG_EXTENSION(x) __has_extension (x)
+#else
+ #define ECB_CLANG_EXTENSION(x) 0
+#endif
+
+#define ECB_CPP (__cplusplus+0)
+#define ECB_CPP11 (__cplusplus >= 201103L)
+
+#if ECB_CPP
+ #define ECB_C 0
+ #define ECB_STDC_VERSION 0
+#else
+ #define ECB_C 1
+ #define ECB_STDC_VERSION __STDC_VERSION__
+#endif
+
+#define ECB_C99 (ECB_STDC_VERSION >= 199901L)
+#define ECB_C11 (ECB_STDC_VERSION >= 201112L)
+
+#if ECB_CPP
+ #define ECB_EXTERN_C extern "C"
+ #define ECB_EXTERN_C_BEG ECB_EXTERN_C {
+ #define ECB_EXTERN_C_END }
+#else
+ #define ECB_EXTERN_C extern
+ #define ECB_EXTERN_C_BEG
+ #define ECB_EXTERN_C_END
+#endif
+
+/*****************************************************************************/
+
+/* ECB_NO_THREADS - ecb is not used by multiple threads, ever */
+/* ECB_NO_SMP - ecb might be used in multiple threads, but only on a single cpu */
+
+#if ECB_NO_THREADS
+ #define ECB_NO_SMP 1
+#endif
+
+#if ECB_NO_SMP
+ #define ECB_MEMORY_FENCE do { } while (0)
+#endif
+
+/* http://www-01.ibm.com/support/knowledgecenter/SSGH3R_13.1.0/com.ibm.xlcpp131.aix.doc/compiler_ref/compiler_builtins.html */
+#if __xlC__ && ECB_CPP
+ #include <builtins.h>
+#endif
+
+#if 1400 <= _MSC_VER
+ #include <intrin.h> /* fence functions _ReadBarrier, also bit search functions _BitScanReverse */
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if ECB_GCC_VERSION(2,5) || defined __INTEL_COMPILER || (__llvm__ && __GNUC__) || __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
+ #if __i386 || __i386__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("lock; orb $0, -1(%%esp)" : : : "memory")
+ #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
+ #elif ECB_GCC_AMD64
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mfence" : : : "memory")
+ #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
+ #elif __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("sync" : : : "memory")
+ #elif defined __ARM_ARCH_2__ \
+ || defined __ARM_ARCH_3__ || defined __ARM_ARCH_3M__ \
+ || defined __ARM_ARCH_4__ || defined __ARM_ARCH_4T__ \
+ || defined __ARM_ARCH_5__ || defined __ARM_ARCH_5E__ \
+ || defined __ARM_ARCH_5T__ || defined __ARM_ARCH_5TE__ \
+ || defined __ARM_ARCH_5TEJ__
+ /* should not need any, unless running old code on newer cpu - arm doesn't support that */
+ #elif defined __ARM_ARCH_6__ || defined __ARM_ARCH_6J__ \
+ || defined __ARM_ARCH_6K__ || defined __ARM_ARCH_6ZK__ \
+ || defined __ARM_ARCH_6T2__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mcr p15,0,%0,c7,c10,5" : : "r" (0) : "memory")
+ #elif defined __ARM_ARCH_7__ || defined __ARM_ARCH_7A__ \
+ || defined __ARM_ARCH_7R__ || defined __ARM_ARCH_7M__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb" : : : "memory")
+ #elif __aarch64__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("dmb ish" : : : "memory")
+ #elif (__sparc || __sparc__) && !(__sparc_v8__ || defined __sparcv8)
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad | #StoreStore | #StoreLoad" : : : "memory")
+ #define ECB_MEMORY_FENCE_ACQUIRE __asm__ __volatile__ ("membar #LoadStore | #LoadLoad" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("membar #LoadStore | #StoreStore")
+ #elif defined __s390__ || defined __s390x__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("bcr 15,0" : : : "memory")
+ #elif defined __mips__
+ /* GNU/Linux emulates sync on mips1 architectures, so we force its use */
+ /* anybody else who still uses mips1 is supposed to send in their version, with detection code. */
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ (".set mips2; sync; .set mips0" : : : "memory")
+ #elif defined __alpha__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mb" : : : "memory")
+ #elif defined __hppa__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
+ #define ECB_MEMORY_FENCE_RELEASE __asm__ __volatile__ ("")
+ #elif defined __ia64__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("mf" : : : "memory")
+ #elif defined __m68k__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
+ #elif defined __m88k__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("tb1 0,%%r0,128" : : : "memory")
+ #elif defined __sh__
+ #define ECB_MEMORY_FENCE __asm__ __volatile__ ("" : : : "memory")
+ #endif
+ #endif
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if ECB_GCC_VERSION(4,7)
+ /* see comment below (stdatomic.h) about the C11 memory model. */
+ #define ECB_MEMORY_FENCE __atomic_thread_fence (__ATOMIC_SEQ_CST)
+ #define ECB_MEMORY_FENCE_ACQUIRE __atomic_thread_fence (__ATOMIC_ACQUIRE)
+ #define ECB_MEMORY_FENCE_RELEASE __atomic_thread_fence (__ATOMIC_RELEASE)
+
+ #elif ECB_CLANG_EXTENSION(c_atomic)
+ /* see comment below (stdatomic.h) about the C11 memory model. */
+ #define ECB_MEMORY_FENCE __c11_atomic_thread_fence (__ATOMIC_SEQ_CST)
+ #define ECB_MEMORY_FENCE_ACQUIRE __c11_atomic_thread_fence (__ATOMIC_ACQUIRE)
+ #define ECB_MEMORY_FENCE_RELEASE __c11_atomic_thread_fence (__ATOMIC_RELEASE)
+
+ #elif ECB_GCC_VERSION(4,4) || defined __INTEL_COMPILER || defined __clang__
+ #define ECB_MEMORY_FENCE __sync_synchronize ()
+ #elif _MSC_VER >= 1500 /* VC++ 2008 */
+ /* apparently, microsoft broke all the memory barrier stuff in Visual Studio 2008... */
+ #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
+ #define ECB_MEMORY_FENCE _ReadWriteBarrier (); MemoryBarrier()
+ #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier (); MemoryBarrier() /* according to msdn, _ReadBarrier is not a load fence */
+ #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier (); MemoryBarrier()
+ #elif _MSC_VER >= 1400 /* VC++ 2005 */
+ #pragma intrinsic(_ReadBarrier,_WriteBarrier,_ReadWriteBarrier)
+ #define ECB_MEMORY_FENCE _ReadWriteBarrier ()
+ #define ECB_MEMORY_FENCE_ACQUIRE _ReadWriteBarrier () /* according to msdn, _ReadBarrier is not a load fence */
+ #define ECB_MEMORY_FENCE_RELEASE _WriteBarrier ()
+ #elif defined _WIN32
+ #include <WinNT.h>
+ #define ECB_MEMORY_FENCE MemoryBarrier () /* actually just xchg on x86... scary */
+ #elif __SUNPRO_C >= 0x5110 || __SUNPRO_CC >= 0x5110
+ #include <mbarrier.h>
+ #define ECB_MEMORY_FENCE __machine_rw_barrier ()
+ #define ECB_MEMORY_FENCE_ACQUIRE __machine_r_barrier ()
+ #define ECB_MEMORY_FENCE_RELEASE __machine_w_barrier ()
+ #elif __xlC__
+ #define ECB_MEMORY_FENCE __sync ()
+ #endif
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if ECB_C11 && !defined __STDC_NO_ATOMICS__
+ /* we assume that these memory fences work on all variables/all memory accesses, */
+ /* not just C11 atomics and atomic accesses */
+ #include <stdatomic.h>
+ /* Unfortunately, neither gcc 4.7 nor clang 3.1 generate any instructions for */
+ /* any fence other than seq_cst, which isn't very efficient for us. */
+ /* Why that is, we don't know - either the C11 memory model is quite useless */
+ /* for most usages, or gcc and clang have a bug */
+ /* I *currently* lean towards the latter, and inefficiently implement */
+ /* all three of ecb's fences as a seq_cst fence */
+ /* Update, gcc-4.8 generates mfence for all c++ fences, but nothing */
+ /* for all __atomic_thread_fence's except seq_cst */
+ #define ECB_MEMORY_FENCE atomic_thread_fence (memory_order_seq_cst)
+ #endif
+#endif
+
+#ifndef ECB_MEMORY_FENCE
+ #if !ECB_AVOID_PTHREADS
+ /*
+ * if you get undefined symbol references to pthread_mutex_lock,
+ * or failure to find pthread.h, then you should implement
+ * the ECB_MEMORY_FENCE operations for your cpu/compiler
+ * OR provide pthread.h and link against the posix thread library
+ * of your system.
+ */
+ #include <pthread.h>
+ #define ECB_NEEDS_PTHREADS 1
+ #define ECB_MEMORY_FENCE_NEEDS_PTHREADS 1
+
+ static pthread_mutex_t ecb_mf_lock = PTHREAD_MUTEX_INITIALIZER;
+ #define ECB_MEMORY_FENCE do { pthread_mutex_lock (&ecb_mf_lock); pthread_mutex_unlock (&ecb_mf_lock); } while (0)
+ #endif
+#endif
+
+#if !defined ECB_MEMORY_FENCE_ACQUIRE && defined ECB_MEMORY_FENCE
+ #define ECB_MEMORY_FENCE_ACQUIRE ECB_MEMORY_FENCE
+#endif
+
+#if !defined ECB_MEMORY_FENCE_RELEASE && defined ECB_MEMORY_FENCE
+ #define ECB_MEMORY_FENCE_RELEASE ECB_MEMORY_FENCE
+#endif
+
+/*****************************************************************************/
+
+#if ECB_CPP
+ #define ecb_inline static inline
+#elif ECB_GCC_VERSION(2,5)
+ #define ecb_inline static __inline__
+#elif ECB_C99
+ #define ecb_inline static inline
+#else
+ #define ecb_inline static
+#endif
+
+#if ECB_GCC_VERSION(3,3)
+ #define ecb_restrict __restrict__
+#elif ECB_C99
+ #define ecb_restrict restrict
+#else
+ #define ecb_restrict
+#endif
+
+typedef int ecb_bool;
+
+#define ECB_CONCAT_(a, b) a ## b
+#define ECB_CONCAT(a, b) ECB_CONCAT_(a, b)
+#define ECB_STRINGIFY_(a) # a
+#define ECB_STRINGIFY(a) ECB_STRINGIFY_(a)
+#define ECB_STRINGIFY_EXPR(expr) ((expr), ECB_STRINGIFY_ (expr))
+
+#define ecb_function_ ecb_inline
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_VERSION(2,8)
+ #define ecb_attribute(attrlist) __attribute__ (attrlist)
+#else
+ #define ecb_attribute(attrlist)
+#endif
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_BUILTIN(__builtin_constant_p)
+ #define ecb_is_constant(expr) __builtin_constant_p (expr)
+#else
+ /* possible C11 impl for integral types
+ typedef struct ecb_is_constant_struct ecb_is_constant_struct;
+ #define ecb_is_constant(expr) _Generic ((1 ? (struct ecb_is_constant_struct *)0 : (void *)((expr) - (expr)), ecb_is_constant_struct *: 0, default: 1)) */
+
+ #define ecb_is_constant(expr) 0
+#endif
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_BUILTIN(__builtin_expect)
+ #define ecb_expect(expr,value) __builtin_expect ((expr),(value))
+#else
+ #define ecb_expect(expr,value) (expr)
+#endif
+
+#if ECB_GCC_VERSION(3,1) || ECB_CLANG_BUILTIN(__builtin_prefetch)
+ #define ecb_prefetch(addr,rw,locality) __builtin_prefetch (addr, rw, locality)
+#else
+ #define ecb_prefetch(addr,rw,locality)
+#endif
+
+/* no emulation for ecb_decltype */
+#if ECB_CPP11
+ // older implementations might have problems with decltype(x)::type, work around it
+ template<class T> struct ecb_decltype_t { typedef T type; };
+ #define ecb_decltype(x) ecb_decltype_t<decltype (x)>::type
+#elif ECB_GCC_VERSION(3,0) || ECB_CLANG_VERSION(2,8)
+ #define ecb_decltype(x) __typeof__ (x)
+#endif
+
+#if _MSC_VER >= 1300
+ #define ecb_deprecated __declspec (deprecated)
+#else
+ #define ecb_deprecated ecb_attribute ((__deprecated__))
+#endif
+
+#if _MSC_VER >= 1500
+ #define ecb_deprecated_message(msg) __declspec (deprecated (msg))
+#elif ECB_GCC_VERSION(4,5)
+ #define ecb_deprecated_message(msg) ecb_attribute ((__deprecated__ (msg))
+#else
+ #define ecb_deprecated_message(msg) ecb_deprecated
+#endif
+
+#if _MSC_VER >= 1400
+ #define ecb_noinline __declspec (noinline)
+#else
+ #define ecb_noinline ecb_attribute ((__noinline__))
+#endif
+
+#define ecb_unused ecb_attribute ((__unused__))
+#define ecb_const ecb_attribute ((__const__))
+#define ecb_pure ecb_attribute ((__pure__))
+
+#if ECB_C11 || __IBMC_NORETURN
+ /* http://www-01.ibm.com/support/knowledgecenter/SSGH3R_13.1.0/com.ibm.xlcpp131.aix.doc/language_ref/noreturn.html */
+ #define ecb_noreturn _Noreturn
+#elif ECB_CPP11
+ #define ecb_noreturn [[noreturn]]
+#elif _MSC_VER >= 1200
+ /* http://msdn.microsoft.com/en-us/library/k6ktzx3s.aspx */
+ #define ecb_noreturn __declspec (noreturn)
+#else
+ #define ecb_noreturn ecb_attribute ((__noreturn__))
+#endif
+
+#if ECB_GCC_VERSION(4,3)
+ #define ecb_artificial ecb_attribute ((__artificial__))
+ #define ecb_hot ecb_attribute ((__hot__))
+ #define ecb_cold ecb_attribute ((__cold__))
+#else
+ #define ecb_artificial
+ #define ecb_hot
+ #define ecb_cold
+#endif
+
+/* put around conditional expressions if you are very sure that the */
+/* expression is mostly true or mostly false. note that these return */
+/* booleans, not the expression. */
+#define ecb_expect_false(expr) ecb_expect (!!(expr), 0)
+#define ecb_expect_true(expr) ecb_expect (!!(expr), 1)
+/* for compatibility to the rest of the world */
+#define ecb_likely(expr) ecb_expect_true (expr)
+#define ecb_unlikely(expr) ecb_expect_false (expr)
+
+/* count trailing zero bits and count # of one bits */
+#if ECB_GCC_VERSION(3,4) \
+ || (ECB_CLANG_BUILTIN(__builtin_clz) && ECB_CLANG_BUILTIN(__builtin_clzll) \
+ && ECB_CLANG_BUILTIN(__builtin_ctz) && ECB_CLANG_BUILTIN(__builtin_ctzll) \
+ && ECB_CLANG_BUILTIN(__builtin_popcount))
+ /* we assume int == 32 bit, long == 32 or 64 bit and long long == 64 bit */
+ #define ecb_ld32(x) (__builtin_clz (x) ^ 31)
+ #define ecb_ld64(x) (__builtin_clzll (x) ^ 63)
+ #define ecb_ctz32(x) __builtin_ctz (x)
+ #define ecb_ctz64(x) __builtin_ctzll (x)
+ #define ecb_popcount32(x) __builtin_popcount (x)
+ /* no popcountll */
+#else
+ ecb_function_ ecb_const int ecb_ctz32 (uint32_t x);
+ ecb_function_ ecb_const int
+ ecb_ctz32 (uint32_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanForward (&r, x);
+ return (int)r;
+#else
+ int r = 0;
+
+ x &= ~x + 1; /* this isolates the lowest bit */
+
+#if ECB_branchless_on_i386
+ r += !!(x & 0xaaaaaaaa) << 0;
+ r += !!(x & 0xcccccccc) << 1;
+ r += !!(x & 0xf0f0f0f0) << 2;
+ r += !!(x & 0xff00ff00) << 3;
+ r += !!(x & 0xffff0000) << 4;
+#else
+ if (x & 0xaaaaaaaa) r += 1;
+ if (x & 0xcccccccc) r += 2;
+ if (x & 0xf0f0f0f0) r += 4;
+ if (x & 0xff00ff00) r += 8;
+ if (x & 0xffff0000) r += 16;
+#endif
+
+ return r;
+#endif
+ }
+
+ ecb_function_ ecb_const int ecb_ctz64 (uint64_t x);
+ ecb_function_ ecb_const int
+ ecb_ctz64 (uint64_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanForward64 (&r, x);
+ return (int)r;
+#else
+ int shift = x & 0xffffffff ? 0 : 32;
+ return ecb_ctz32 (x >> shift) + shift;
+#endif
+ }
+
+ ecb_function_ ecb_const int ecb_popcount32 (uint32_t x);
+ ecb_function_ ecb_const int
+ ecb_popcount32 (uint32_t x)
+ {
+ x -= (x >> 1) & 0x55555555;
+ x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
+ x = ((x >> 4) + x) & 0x0f0f0f0f;
+ x *= 0x01010101;
+
+ return x >> 24;
+ }
+
+ ecb_function_ ecb_const int ecb_ld32 (uint32_t x);
+ ecb_function_ ecb_const int ecb_ld32 (uint32_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_IX86 || _M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanReverse (&r, x);
+ return (int)r;
+#else
+ int r = 0;
+
+ if (x >> 16) { x >>= 16; r += 16; }
+ if (x >> 8) { x >>= 8; r += 8; }
+ if (x >> 4) { x >>= 4; r += 4; }
+ if (x >> 2) { x >>= 2; r += 2; }
+ if (x >> 1) { r += 1; }
+
+ return r;
+#endif
+ }
+
+ ecb_function_ ecb_const int ecb_ld64 (uint64_t x);
+ ecb_function_ ecb_const int ecb_ld64 (uint64_t x)
+ {
+#if 1400 <= _MSC_VER && (_M_X64 || _M_IA64 || _M_ARM)
+ unsigned long r;
+ _BitScanReverse64 (&r, x);
+ return (int)r;
+#else
+ int r = 0;
+
+ if (x >> 32) { x >>= 32; r += 32; }
+
+ return r + ecb_ld32 (x);
+#endif
+ }
+#endif
+
+ecb_function_ ecb_const ecb_bool ecb_is_pot32 (uint32_t x);
+ecb_function_ ecb_const ecb_bool ecb_is_pot32 (uint32_t x) { return !(x & (x - 1)); }
+ecb_function_ ecb_const ecb_bool ecb_is_pot64 (uint64_t x);
+ecb_function_ ecb_const ecb_bool ecb_is_pot64 (uint64_t x) { return !(x & (x - 1)); }
+
+ecb_function_ ecb_const uint8_t ecb_bitrev8 (uint8_t x);
+ecb_function_ ecb_const uint8_t ecb_bitrev8 (uint8_t x)
+{
+ return ( (x * 0x0802U & 0x22110U)
+ | (x * 0x8020U & 0x88440U)) * 0x10101U >> 16;
+}
+
+ecb_function_ ecb_const uint16_t ecb_bitrev16 (uint16_t x);
+ecb_function_ ecb_const uint16_t ecb_bitrev16 (uint16_t x)
+{
+ x = ((x >> 1) & 0x5555) | ((x & 0x5555) << 1);
+ x = ((x >> 2) & 0x3333) | ((x & 0x3333) << 2);
+ x = ((x >> 4) & 0x0f0f) | ((x & 0x0f0f) << 4);
+ x = ( x >> 8 ) | ( x << 8);
+
+ return x;
+}
+
+ecb_function_ ecb_const uint32_t ecb_bitrev32 (uint32_t x);
+ecb_function_ ecb_const uint32_t ecb_bitrev32 (uint32_t x)
+{
+ x = ((x >> 1) & 0x55555555) | ((x & 0x55555555) << 1);
+ x = ((x >> 2) & 0x33333333) | ((x & 0x33333333) << 2);
+ x = ((x >> 4) & 0x0f0f0f0f) | ((x & 0x0f0f0f0f) << 4);
+ x = ((x >> 8) & 0x00ff00ff) | ((x & 0x00ff00ff) << 8);
+ x = ( x >> 16 ) | ( x << 16);
+
+ return x;
+}
+
+/* popcount64 is only available on 64 bit cpus as gcc builtin */
+/* so for this version we are lazy */
+ecb_function_ ecb_const int ecb_popcount64 (uint64_t x);
+ecb_function_ ecb_const int
+ecb_popcount64 (uint64_t x)
+{
+ return ecb_popcount32 (x) + ecb_popcount32 (x >> 32);
+}
+
+ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count);
+ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count);
+ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count);
+ecb_inline ecb_const uint16_t ecb_rotr16 (uint16_t x, unsigned int count);
+ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count);
+ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count);
+ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count);
+ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count);
+
+ecb_inline ecb_const uint8_t ecb_rotl8 (uint8_t x, unsigned int count) { return (x >> ( 8 - count)) | (x << count); }
+ecb_inline ecb_const uint8_t ecb_rotr8 (uint8_t x, unsigned int count) { return (x << ( 8 - count)) | (x >> count); }
+ecb_inline ecb_const uint16_t ecb_rotl16 (uint16_t x, unsigned int count) { return (x >> (16 - count)) | (x << count); }
+ecb_inline ecb_const uint16_t ecb_rotr16 (uint16_t x, unsigned int count) { return (x << (16 - count)) | (x >> count); }
+ecb_inline ecb_const uint32_t ecb_rotl32 (uint32_t x, unsigned int count) { return (x >> (32 - count)) | (x << count); }
+ecb_inline ecb_const uint32_t ecb_rotr32 (uint32_t x, unsigned int count) { return (x << (32 - count)) | (x >> count); }
+ecb_inline ecb_const uint64_t ecb_rotl64 (uint64_t x, unsigned int count) { return (x >> (64 - count)) | (x << count); }
+ecb_inline ecb_const uint64_t ecb_rotr64 (uint64_t x, unsigned int count) { return (x << (64 - count)) | (x >> count); }
+
+#if ECB_GCC_VERSION(4,3) || (ECB_CLANG_BUILTIN(__builtin_bswap32) && ECB_CLANG_BUILTIN(__builtin_bswap64))
+ #if ECB_GCC_VERSION(4,8) || ECB_CLANG_BUILTIN(__builtin_bswap16)
+ #define ecb_bswap16(x) __builtin_bswap16 (x)
+ #else
+ #define ecb_bswap16(x) (__builtin_bswap32 (x) >> 16)
+ #endif
+ #define ecb_bswap32(x) __builtin_bswap32 (x)
+ #define ecb_bswap64(x) __builtin_bswap64 (x)
+#elif _MSC_VER
+ #include <stdlib.h>
+ #define ecb_bswap16(x) ((uint16_t)_byteswap_ushort ((uint16_t)(x)))
+ #define ecb_bswap32(x) ((uint32_t)_byteswap_ulong ((uint32_t)(x)))
+ #define ecb_bswap64(x) ((uint64_t)_byteswap_uint64 ((uint64_t)(x)))
+#else
+ ecb_function_ ecb_const uint16_t ecb_bswap16 (uint16_t x);
+ ecb_function_ ecb_const uint16_t
+ ecb_bswap16 (uint16_t x)
+ {
+ return ecb_rotl16 (x, 8);
+ }
+
+ ecb_function_ ecb_const uint32_t ecb_bswap32 (uint32_t x);
+ ecb_function_ ecb_const uint32_t
+ ecb_bswap32 (uint32_t x)
+ {
+ return (((uint32_t)ecb_bswap16 (x)) << 16) | ecb_bswap16 (x >> 16);
+ }
+
+ ecb_function_ ecb_const uint64_t ecb_bswap64 (uint64_t x);
+ ecb_function_ ecb_const uint64_t
+ ecb_bswap64 (uint64_t x)
+ {
+ return (((uint64_t)ecb_bswap32 (x)) << 32) | ecb_bswap32 (x >> 32);
+ }
+#endif
+
+#if ECB_GCC_VERSION(4,5) || ECB_CLANG_BUILTIN(__builtin_unreachable)
+ #define ecb_unreachable() __builtin_unreachable ()
+#else
+ /* this seems to work fine, but gcc always emits a warning for it :/ */
+ ecb_inline ecb_noreturn void ecb_unreachable (void);
+ ecb_inline ecb_noreturn void ecb_unreachable (void) { }
+#endif
+
+/* try to tell the compiler that some condition is definitely true */
+#define ecb_assume(cond) if (!(cond)) ecb_unreachable (); else 0
+
+ecb_inline ecb_const uint32_t ecb_byteorder_helper (void);
+ecb_inline ecb_const uint32_t
+ecb_byteorder_helper (void)
+{
+ /* the union code still generates code under pressure in gcc, */
+ /* but less than using pointers, and always seems to */
+ /* successfully return a constant. */
+ /* the reason why we have this horrible preprocessor mess */
+ /* is to avoid it in all cases, at least on common architectures */
+ /* or when using a recent enough gcc version (>= 4.6) */
+#if (defined __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__) \
+ || ((__i386 || __i386__ || _M_IX86 || ECB_GCC_AMD64 || ECB_MSVC_AMD64) && !__VOS__)
+ #define ECB_LITTLE_ENDIAN 1
+ return 0x44332211;
+#elif (defined __BYTE_ORDER__ && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__) \
+ || ((__AARCH64EB__ || __MIPSEB__ || __ARMEB__) && !__VOS__)
+ #define ECB_BIG_ENDIAN 1
+ return 0x11223344;
+#else
+ union
+ {
+ uint8_t c[4];
+ uint32_t u;
+ } u = { 0x11, 0x22, 0x33, 0x44 };
+ return u.u;
+#endif
+}
+
+ecb_inline ecb_const ecb_bool ecb_big_endian (void);
+ecb_inline ecb_const ecb_bool ecb_big_endian (void) { return ecb_byteorder_helper () == 0x11223344; }
+ecb_inline ecb_const ecb_bool ecb_little_endian (void);
+ecb_inline ecb_const ecb_bool ecb_little_endian (void) { return ecb_byteorder_helper () == 0x44332211; }
+
+#if ECB_GCC_VERSION(3,0) || ECB_C99
+ #define ecb_mod(m,n) ((m) % (n) + ((m) % (n) < 0 ? (n) : 0))
+#else
+ #define ecb_mod(m,n) ((m) < 0 ? ((n) - 1 - ((-1 - (m)) % (n))) : ((m) % (n)))
+#endif
+
+#if ECB_CPP
+ template<typename T>
+ static inline T ecb_div_rd (T val, T div)
+ {
+ return val < 0 ? - ((-val + div - 1) / div) : (val ) / div;
+ }
+ template<typename T>
+ static inline T ecb_div_ru (T val, T div)
+ {
+ return val < 0 ? - ((-val ) / div) : (val + div - 1) / div;
+ }
+#else
+ #define ecb_div_rd(val,div) ((val) < 0 ? - ((-(val) + (div) - 1) / (div)) : ((val) ) / (div))
+ #define ecb_div_ru(val,div) ((val) < 0 ? - ((-(val) ) / (div)) : ((val) + (div) - 1) / (div))
+#endif
+
+#if ecb_cplusplus_does_not_suck
+ /* does not work for local types (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2657.htm) */
+ template<typename T, int N>
+ static inline int ecb_array_length (const T (&arr)[N])
+ {
+ return N;
+ }
+#else
+ #define ecb_array_length(name) (sizeof (name) / sizeof (name [0]))
+#endif
+
+ecb_function_ ecb_const uint32_t ecb_binary16_to_binary32 (uint32_t x);
+ecb_function_ ecb_const uint32_t
+ecb_binary16_to_binary32 (uint32_t x)
+{
+ unsigned int s = (x & 0x8000) << (31 - 15);
+ int e = (x >> 10) & 0x001f;
+ unsigned int m = x & 0x03ff;
+
+ if (ecb_expect_false (e == 31))
+ /* infinity or NaN */
+ e = 255 - (127 - 15);
+ else if (ecb_expect_false (!e))
+ {
+ if (ecb_expect_true (!m))
+ /* zero, handled by code below by forcing e to 0 */
+ e = 0 - (127 - 15);
+ else
+ {
+ /* subnormal, renormalise */
+ unsigned int s = 10 - ecb_ld32 (m);
+
+ m = (m << s) & 0x3ff; /* mask implicit bit */
+ e -= s - 1;
+ }
+ }
+
+ /* e and m now are normalised, or zero, (or inf or nan) */
+ e += 127 - 15;
+
+ return s | (e << 23) | (m << (23 - 10));
+}
+
+ecb_function_ ecb_const uint16_t ecb_binary32_to_binary16 (uint32_t x);
+ecb_function_ ecb_const uint16_t
+ecb_binary32_to_binary16 (uint32_t x)
+{
+ unsigned int s = (x >> 16) & 0x00008000; /* sign bit, the easy part */
+ unsigned int e = ((x >> 23) & 0x000000ff) - (127 - 15); /* the desired exponent */
+ unsigned int m = x & 0x007fffff;
+
+ x &= 0x7fffffff;
+
+ /* if it's within range of binary16 normals, use fast path */
+ if (ecb_expect_true (0x38800000 <= x && x <= 0x477fefff))
+ {
+ /* mantissa round-to-even */
+ m += 0x00000fff + ((m >> (23 - 10)) & 1);
+
+ /* handle overflow */
+ if (ecb_expect_false (m >= 0x00800000))
+ {
+ m >>= 1;
+ e += 1;
+ }
+
+ return s | (e << 10) | (m >> (23 - 10));
+ }
+
+ /* handle large numbers and infinity */
+ if (ecb_expect_true (0x477fefff < x && x <= 0x7f800000))
+ return s | 0x7c00;
+
+ /* handle zero, subnormals and small numbers */
+ if (ecb_expect_true (x < 0x38800000))
+ {
+ /* zero */
+ if (ecb_expect_true (!x))
+ return s;
+
+ /* handle subnormals */
+
+ /* too small, will be zero */
+ if (e < (14 - 24)) /* might not be sharp, but is good enough */
+ return s;
+
+ m |= 0x00800000; /* make implicit bit explicit */
+
+ /* very tricky - we need to round to the nearest e (+10) bit value */
+ {
+ unsigned int bits = 14 - e;
+ unsigned int half = (1 << (bits - 1)) - 1;
+ unsigned int even = (m >> bits) & 1;
+
+ /* if this overflows, we will end up with a normalised number */
+ m = (m + half + even) >> bits;
+ }
+
+ return s | m;
+ }
+
+ /* handle NaNs, preserve leftmost nan bits, but make sure we don't turn them into infinities */
+ m >>= 13;
+
+ return s | 0x7c00 | m | !m;
+}
+
+/*******************************************************************************/
+/* floating point stuff, can be disabled by defining ECB_NO_LIBM */
+
+/* basically, everything uses "ieee pure-endian" floating point numbers */
+/* the only noteworthy exception is ancient armle, which uses order 43218765 */
+#if 0 \
+ || __i386 || __i386__ \
+ || ECB_GCC_AMD64 \
+ || __powerpc__ || __ppc__ || __powerpc64__ || __ppc64__ \
+ || defined __s390__ || defined __s390x__ \
+ || defined __mips__ \
+ || defined __alpha__ \
+ || defined __hppa__ \
+ || defined __ia64__ \
+ || defined __m68k__ \
+ || defined __m88k__ \
+ || defined __sh__ \
+ || defined _M_IX86 || defined ECB_MSVC_AMD64 || defined _M_IA64 \
+ || (defined __arm__ && (defined __ARM_EABI__ || defined __EABI__ || defined __VFP_FP__ || defined _WIN32_WCE || defined __ANDROID__)) \
+ || defined __aarch64__
+ #define ECB_STDFP 1
+ #include <string.h> /* for memcpy */
+#else
+ #define ECB_STDFP 0
+#endif
+
+#ifndef ECB_NO_LIBM
+
+ #include <math.h> /* for frexp*, ldexp*, INFINITY, NAN */
+
+ /* only the oldest of old doesn't have this one. solaris. */
+ #ifdef INFINITY
+ #define ECB_INFINITY INFINITY
+ #else
+ #define ECB_INFINITY HUGE_VAL
+ #endif
+
+ #ifdef NAN
+ #define ECB_NAN NAN
+ #else
+ #define ECB_NAN ECB_INFINITY
+ #endif
+
+ #if ECB_C99 || _XOPEN_VERSION >= 600 || _POSIX_VERSION >= 200112L
+ #define ecb_ldexpf(x,e) ldexpf ((x), (e))
+ #define ecb_frexpf(x,e) frexpf ((x), (e))
+ #else
+ #define ecb_ldexpf(x,e) (float) ldexp ((double) (x), (e))
+ #define ecb_frexpf(x,e) (float) frexp ((double) (x), (e))
+ #endif
+
+ /* convert a float to ieee single/binary32 */
+ ecb_function_ ecb_const uint32_t ecb_float_to_binary32 (float x);
+ ecb_function_ ecb_const uint32_t
+ ecb_float_to_binary32 (float x)
+ {
+ uint32_t r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 4);
+ #else
+ /* slow emulation, works for anything but -0 */
+ uint32_t m;
+ int e;
+
+ if (x == 0e0f ) return 0x00000000U;
+ if (x > +3.40282346638528860e+38f) return 0x7f800000U;
+ if (x < -3.40282346638528860e+38f) return 0xff800000U;
+ if (x != x ) return 0x7fbfffffU;
+
+ m = ecb_frexpf (x, &e) * 0x1000000U;
+
+ r = m & 0x80000000U;
+
+ if (r)
+ m = -m;
+
+ if (e <= -126)
+ {
+ m &= 0xffffffU;
+ m >>= (-125 - e);
+ e = -126;
+ }
+
+ r |= (e + 126) << 23;
+ r |= m & 0x7fffffU;
+ #endif
+
+ return r;
+ }
+
+ /* converts an ieee single/binary32 to a float */
+ ecb_function_ ecb_const float ecb_binary32_to_float (uint32_t x);
+ ecb_function_ ecb_const float
+ ecb_binary32_to_float (uint32_t x)
+ {
+ float r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 4);
+ #else
+ /* emulation, only works for normals and subnormals and +0 */
+ int neg = x >> 31;
+ int e = (x >> 23) & 0xffU;
+
+ x &= 0x7fffffU;
+
+ if (e)
+ x |= 0x800000U;
+ else
+ e = 1;
+
+ /* we distrust ldexpf a bit and do the 2**-24 scaling by an extra multiply */
+ r = ecb_ldexpf (x * (0.5f / 0x800000U), e - 126);
+
+ r = neg ? -r : r;
+ #endif
+
+ return r;
+ }
+
+ /* convert a double to ieee double/binary64 */
+ ecb_function_ ecb_const uint64_t ecb_double_to_binary64 (double x);
+ ecb_function_ ecb_const uint64_t
+ ecb_double_to_binary64 (double x)
+ {
+ uint64_t r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 8);
+ #else
+ /* slow emulation, works for anything but -0 */
+ uint64_t m;
+ int e;
+
+ if (x == 0e0 ) return 0x0000000000000000U;
+ if (x > +1.79769313486231470e+308) return 0x7ff0000000000000U;
+ if (x < -1.79769313486231470e+308) return 0xfff0000000000000U;
+ if (x != x ) return 0X7ff7ffffffffffffU;
+
+ m = frexp (x, &e) * 0x20000000000000U;
+
+ r = m & 0x8000000000000000;;
+
+ if (r)
+ m = -m;
+
+ if (e <= -1022)
+ {
+ m &= 0x1fffffffffffffU;
+ m >>= (-1021 - e);
+ e = -1022;
+ }
+
+ r |= ((uint64_t)(e + 1022)) << 52;
+ r |= m & 0xfffffffffffffU;
+ #endif
+
+ return r;
+ }
+
+ /* converts an ieee double/binary64 to a double */
+ ecb_function_ ecb_const double ecb_binary64_to_double (uint64_t x);
+ ecb_function_ ecb_const double
+ ecb_binary64_to_double (uint64_t x)
+ {
+ double r;
+
+ #if ECB_STDFP
+ memcpy (&r, &x, 8);
+ #else
+ /* emulation, only works for normals and subnormals and +0 */
+ int neg = x >> 63;
+ int e = (x >> 52) & 0x7ffU;
+
+ x &= 0xfffffffffffffU;
+
+ if (e)
+ x |= 0x10000000000000U;
+ else
+ e = 1;
+
+ /* we distrust ldexp a bit and do the 2**-53 scaling by an extra multiply */
+ r = ldexp (x * (0.5 / 0x10000000000000U), e - 1022);
+
+ r = neg ? -r : r;
+ #endif
+
+ return r;
+ }
+
+ /* convert a float to ieee half/binary16 */
+ ecb_function_ ecb_const uint16_t ecb_float_to_binary16 (float x);
+ ecb_function_ ecb_const uint16_t
+ ecb_float_to_binary16 (float x)
+ {
+ return ecb_binary32_to_binary16 (ecb_float_to_binary32 (x));
+ }
+
+ /* convert an ieee half/binary16 to float */
+ ecb_function_ ecb_const float ecb_binary16_to_float (uint16_t x);
+ ecb_function_ ecb_const float
+ ecb_binary16_to_float (uint16_t x)
+ {
+ return ecb_binary32_to_float (ecb_binary16_to_binary32 (x));
+ }
+
+#endif
+
+#endif
+
--- rxvt-unicode/libecb/ecb.pod
+++ rxvt-unicode/libecb/ecb.pod
@@ -0,0 +1,881 @@
+=head1 LIBECB - e-C-Builtins
+
+=head2 ABOUT LIBECB
+
+Libecb is currently a simple header file that doesn't require any
+configuration to use or include in your project.
+
+It's part of the e-suite of libraries, other members of which include
+libev and libeio.
+
+Its homepage can be found here:
+
+ http://software.schmorp.de/pkg/libecb
+
+It mainly provides a number of wrappers around GCC built-ins, together
+with replacement functions for other compilers. In addition to this,
+it provides a number of other lowlevel C utilities, such as endianness
+detection, byte swapping or bit rotations.
+
+Or in other words, things that should be built into any standard C system,
+but aren't, implemented as efficient as possible with GCC, and still
+correct with other compilers.
+
+More might come.
+
+=head2 ABOUT THE HEADER
+
+At the moment, all you have to do is copy F<ecb.h> somewhere where your
+compiler can find it and include it:
+
+ #include <ecb.h>
+
+The header should work fine for both C and C++ compilation, and gives you
+all of F<inttypes.h> in addition to the ECB symbols.
+
+There are currently no object files to link to - future versions might
+come with an (optional) object code library to link against, to reduce
+code size or gain access to additional features.
+
+It also currently includes everything from F<inttypes.h>.
+
+=head2 ABOUT THIS MANUAL / CONVENTIONS
+
+This manual mainly describes each (public) function available after
+including the F<ecb.h> header. The header might define other symbols than
+these, but these are not part of the public API, and not supported in any
+way.
+
+When the manual mentions a "function" then this could be defined either as
+as inline function, a macro, or an external symbol.
+
+When functions use a concrete standard type, such as C<int> or
+C<uint32_t>, then the corresponding function works only with that type. If
+only a generic name is used (C<expr>, C<cond>, C<value> and so on), then
+the corresponding function relies on C to implement the correct types, and
+is usually implemented as a macro. Specifically, a "bool" in this manual
+refers to any kind of boolean value, not a specific type.
+
+=head2 TYPES / TYPE SUPPORT
+
+ecb.h makes sure that the following types are defined (in the expected way):
+
+ int8_t uint8_t int16_t uint16_t
+ int32_t uint32_t int64_t uint64_t
+ intptr_t uintptr_t
+
+The macro C<ECB_PTRSIZE> is defined to the size of a pointer on this
+platform (currently C<4> or C<8>) and can be used in preprocessor
+expressions.
+
+For C<ptrdiff_t> and C<size_t> use C<stddef.h>.
+
+=head2 LANGUAGE/ENVIRONMENT/COMPILER VERSIONS
+
+All the following symbols expand to an expression that can be tested in
+preprocessor instructions as well as treated as a boolean (use C<!!> to
+ensure it's either C<0> or C<1> if you need that).
+
+=over 4
+
+=item ECB_C
+
+True if the implementation defines the C<__STDC__> macro to a true value,
+while not claiming to be C++.
+
+=item ECB_C99
+
+True if the implementation claims to be compliant to C99 (ISO/IEC
+9899:1999) or any later version, while not claiming to be C++.
+
+Note that later versions (ECB_C11) remove core features again (for
+example, variable length arrays).
+
+=item ECB_C11
+
+True if the implementation claims to be compliant to C11 (ISO/IEC
+9899:2011) or any later version, while not claiming to be C++.
+
+=item ECB_CPP
+
+True if the implementation defines the C<__cplusplus__> macro to a true
+value, which is typically true for C++ compilers.
+
+=item ECB_CPP11
+
+True if the implementation claims to be compliant to ISO/IEC 14882:2011
+(C++11) or any later version.
+
+=item ECB_GCC_VERSION (major, minor)
+
+Expands to a true value (suitable for testing in by the preprocessor)
+if the compiler used is GNU C and the version is the given version, or
+higher.
+
+This macro tries to return false on compilers that claim to be GCC
+compatible but aren't.
+
+=item ECB_EXTERN_C
+
+Expands to C<extern "C"> in C++, and a simple C<extern> in C.
+
+This can be used to declare a single external C function:
+
+ ECB_EXTERN_C int printf (const char *format, ...);
+
+=item ECB_EXTERN_C_BEG / ECB_EXTERN_C_END
+
+These two macros can be used to wrap multiple C<extern "C"> definitions -
+they expand to nothing in C.
+
+They are most useful in header files:
+
+ ECB_EXTERN_C_BEG
+
+ int mycfun1 (int x);
+ int mycfun2 (int x);
+
+ ECB_EXTERN_C_END
+
+=item ECB_STDFP
+
+If this evaluates to a true value (suitable for testing in by the
+preprocessor), then C<float> and C<double> use IEEE 754 single/binary32
+and double/binary64 representations internally I<and> the endianness of
+both types match the endianness of C<uint32_t> and C<uint64_t>.
+
+This means you can just copy the bits of a C<float> (or C<double>) to an
+C<uint32_t> (or C<uint64_t>) and get the raw IEEE 754 bit representation
+without having to think about format or endianness.
+
+This is true for basically all modern platforms, although F<ecb.h> might
+not be able to deduce this correctly everywhere and might err on the safe
+side.
+
+=item ECB_AMD64, ECB_AMD64_X32
+
+These two macros are defined to C<1> on the x86_64/amd64 ABI and the X32
+ABI, respectively, and undefined elsewhere.
+
+The designers of the new X32 ABI for some inexplicable reason decided to
+make it look exactly like amd64, even though it's completely incompatible
+to that ABI, breaking about every piece of software that assumed that
+C<__x86_64> stands for, well, the x86-64 ABI, making these macros
+necessary.
+
+=back
+
+=head2 MACRO TRICKERY
+
+=over 4
+
+=item ECB_CONCAT (a, b)
+
+Expands any macros in C<a> and C<b>, then concatenates the result to form
+a single token. This is mainly useful to form identifiers from components,
+e.g.:
+
+ #define S1 str
+ #define S2 cpy
+
+ ECB_CONCAT (S1, S2)(dst, src); // == strcpy (dst, src);
+
+=item ECB_STRINGIFY (arg)
+
+Expands any macros in C<arg> and returns the stringified version of
+it. This is mainly useful to get the contents of a macro in string form,
+e.g.:
+
+ #define SQL_LIMIT 100
+ sql_exec ("select * from table limit " ECB_STRINGIFY (SQL_LIMIT));
+
+=item ECB_STRINGIFY_EXPR (expr)
+
+Like C<ECB_STRINGIFY>, but additionally evaluates C<expr> to make sure it
+is a valid expression. This is useful to catch typos or cases where the
+macro isn't available:
+
+ #include <errno.h>
+
+ ECB_STRINGIFY (EDOM); // "33" (on my system at least)
+ ECB_STRINGIFY_EXPR (EDOM); // "33"
+
+ // now imagine we had a typo:
+
+ ECB_STRINGIFY (EDAM); // "EDAM"
+ ECB_STRINGIFY_EXPR (EDAM); // error: EDAM undefined
+
+=back
+
+=head2 ATTRIBUTES
+
+A major part of libecb deals with additional attributes that can be
+assigned to functions, variables and sometimes even types - much like
+C<const> or C<volatile> in C. They are implemented using either GCC
+attributes or other compiler/language specific features. Attributes
+declarations must be put before the whole declaration:
+
+ ecb_const int mysqrt (int a);
+ ecb_unused int i;
+
+=over 4
+
+=item ecb_unused
+
+Marks a function or a variable as "unused", which simply suppresses a
+warning by GCC when it detects it as unused. This is useful when you e.g.
+declare a variable but do not always use it:
+
+ {
+ ecb_unused int var;
+
+ #ifdef SOMECONDITION
+ var = ...;
+ return var;
+ #else
+ return 0;
+ #endif
+ }
+
+=item ecb_deprecated
+
+Similar to C<ecb_unused>, but marks a function, variable or type as
+deprecated. This makes some compilers warn when the type is used.
+
+=item ecb_deprecated_message (message)
+
+Same as C<ecb_deprecated>, but if possible, the specified diagnostic is
+used instead of a generic depreciation message when the object is being
+used.
+
+=item ecb_inline
+
+Expands either to (a compiler-specific equivalent of) C<static inline> or
+to just C<static>, if inline isn't supported. It should be used to declare
+functions that should be inlined, for code size or speed reasons.
+
+Example: inline this function, it surely will reduce codesize.
+
+ ecb_inline int
+ negmul (int a, int b)
+ {
+ return - (a * b);
+ }
+
+=item ecb_noinline
+
+Prevents a function from being inlined - it might be optimised away, but
+not inlined into other functions. This is useful if you know your function
+is rarely called and large enough for inlining not to be helpful.
+
+=item ecb_noreturn
+
+Marks a function as "not returning, ever". Some typical functions that
+don't return are C<exit> or C<abort> (which really works hard to not
+return), and now you can make your own:
+
+ ecb_noreturn void
+ my_abort (const char *errline)
+ {
+ puts (errline);
+ abort ();
+ }
+
+In this case, the compiler would probably be smart enough to deduce it on
+its own, so this is mainly useful for declarations.
+
+=item ecb_restrict
+
+Expands to the C<restrict> keyword or equivalent on compilers that support
+them, and to nothing on others. Must be specified on a pointer type or
+an array index to indicate that the memory doesn't alias with any other
+restricted pointer in the same scope.
+
+Example: multiply a vector, and allow the compiler to parallelise the
+loop, because it knows it doesn't overwrite input values.
+
+ void
+ multiply (ecb_restrict float *src,
+ ecb_restrict float *dst,
+ int len, float factor)
+ {
+ int i;
+
+ for (i = 0; i < len; ++i)
+ dst [i] = src [i] * factor;
+ }
+
+=item ecb_const
+
+Declares that the function only depends on the values of its arguments,
+much like a mathematical function. It specifically does not read or write
+any memory any arguments might point to, global variables, or call any
+non-const functions. It also must not have any side effects.
+
+Such a function can be optimised much more aggressively by the compiler -
+for example, multiple calls with the same arguments can be optimised into
+a single call, which wouldn't be possible if the compiler would have to
+expect any side effects.
+
+It is best suited for functions in the sense of mathematical functions,
+such as a function returning the square root of its input argument.
+
+Not suited would be a function that calculates the hash of some memory
+area you pass in, prints some messages or looks at a global variable to
+decide on rounding.
+
+See C<ecb_pure> for a slightly less restrictive class of functions.
+
+=item ecb_pure
+
+Similar to C<ecb_const>, declares a function that has no side
+effects. Unlike C<ecb_const>, the function is allowed to examine global
+variables and any other memory areas (such as the ones passed to it via
+pointers).
+
+While these functions cannot be optimised as aggressively as C<ecb_const>
+functions, they can still be optimised away in many occasions, and the
+compiler has more freedom in moving calls to them around.
+
+Typical examples for such functions would be C<strlen> or C<memcmp>. A
+function that calculates the MD5 sum of some input and updates some MD5
+state passed as argument would I<NOT> be pure, however, as it would modify
+some memory area that is not the return value.
+
+=item ecb_hot
+
+This declares a function as "hot" with regards to the cache - the function
+is used so often, that it is very beneficial to keep it in the cache if
+possible.
+
+The compiler reacts by trying to place hot functions near to each other in
+memory.
+
+Whether a function is hot or not often depends on the whole program,
+and less on the function itself. C<ecb_cold> is likely more useful in
+practise.
+
+=item ecb_cold
+
+The opposite of C<ecb_hot> - declares a function as "cold" with regards to
+the cache, or in other words, this function is not called often, or not at
+speed-critical times, and keeping it in the cache might be a waste of said
+cache.
+
+In addition to placing cold functions together (or at least away from hot
+functions), this knowledge can be used in other ways, for example, the
+function will be optimised for size, as opposed to speed, and codepaths
+leading to calls to those functions can automatically be marked as if
+C<ecb_expect_false> had been used to reach them.
+
+Good examples for such functions would be error reporting functions, or
+functions only called in exceptional or rare cases.
+
+=item ecb_artificial
+
+Declares the function as "artificial", in this case meaning that this
+function is not really meant to be a function, but more like an accessor
+- many methods in C++ classes are mere accessor functions, and having a
+crash reported in such a method, or single-stepping through them, is not
+usually so helpful, especially when it's inlined to just a few instructions.
+
+Marking them as artificial will instruct the debugger about just this,
+leading to happier debugging and thus happier lives.
+
+Example: in some kind of smart-pointer class, mark the pointer accessor as
+artificial, so that the whole class acts more like a pointer and less like
+some C++ abstraction monster.
+
+ template<typename T>
+ struct my_smart_ptr
+ {
+ T *value;
+
+ ecb_artificial
+ operator T *()
+ {
+ return value;
+ }
+ };
+
+=back
+
+=head2 OPTIMISATION HINTS
+
+=over 4
+
+=item bool ecb_is_constant (expr)
+
+Returns true iff the expression can be deduced to be a compile-time
+constant, and false otherwise.
+
+For example, when you have a C<rndm16> function that returns a 16 bit
+random number, and you have a function that maps this to a range from
+0..n-1, then you could use this inline function in a header file:
+
+ ecb_inline uint32_t
+ rndm (uint32_t n)
+ {
+ return (n * (uint32_t)rndm16 ()) >> 16;
+ }
+
+However, for powers of two, you could use a normal mask, but that is only
+worth it if, at compile time, you can detect this case. This is the case
+when the passed number is a constant and also a power of two (C<n & (n -
+1) == 0>):
+
+ ecb_inline uint32_t
+ rndm (uint32_t n)
+ {
+ return is_constant (n) && !(n & (n - 1))
+ ? rndm16 () & (num - 1)
+ : (n * (uint32_t)rndm16 ()) >> 16;
+ }
+
+=item ecb_expect (expr, value)
+
+Evaluates C<expr> and returns it. In addition, it tells the compiler that
+the C<expr> evaluates to C<value> a lot, which can be used for static
+branch optimisations.
+
+Usually, you want to use the more intuitive C<ecb_expect_true> and
+C<ecb_expect_false> functions instead.
+
+=item bool ecb_expect_true (cond)
+
+=item bool ecb_expect_false (cond)
+
+These two functions expect a expression that is true or false and return
+C<1> or C<0>, respectively, so when used in the condition of an C<if> or
+other conditional statement, it will not change the program:
+
+ /* these two do the same thing */
+ if (some_condition) ...;
+ if (ecb_expect_true (some_condition)) ...;
+
+However, by using C<ecb_expect_true>, you tell the compiler that the
+condition is likely to be true (and for C<ecb_expect_false>, that it is
+unlikely to be true).
+
+For example, when you check for a null pointer and expect this to be a
+rare, exceptional, case, then use C<ecb_expect_false>:
+
+ void my_free (void *ptr)
+ {
+ if (ecb_expect_false (ptr == 0))
+ return;
+ }
+
+Consequent use of these functions to mark away exceptional cases or to
+tell the compiler what the hot path through a function is can increase
+performance considerably.
+
+You might know these functions under the name C<likely> and C<unlikely>
+- while these are common aliases, we find that the expect name is easier
+to understand when quickly skimming code. If you wish, you can use
+C<ecb_likely> instead of C<ecb_expect_true> and C<ecb_unlikely> instead of
+C<ecb_expect_false> - these are simply aliases.
+
+A very good example is in a function that reserves more space for some
+memory block (for example, inside an implementation of a string stream) -
+each time something is added, you have to check for a buffer overrun, but
+you expect that most checks will turn out to be false:
+
+ /* make sure we have "size" extra room in our buffer */
+ ecb_inline void
+ reserve (int size)
+ {
+ if (ecb_expect_false (current + size > end))
+ real_reserve_method (size); /* presumably noinline */
+ }
+
+=item ecb_assume (cond)
+
+Tries to tell the compiler that some condition is true, even if it's not
+obvious. This is not a function, but a statement: it cannot be used in
+another expression.
+
+This can be used to teach the compiler about invariants or other
+conditions that might improve code generation, but which are impossible to
+deduce form the code itself.
+
+For example, the example reservation function from the C<ecb_expect_false>
+description could be written thus (only C<ecb_assume> was added):
+
+ ecb_inline void
+ reserve (int size)
+ {
+ if (ecb_expect_false (current + size > end))
+ real_reserve_method (size); /* presumably noinline */
+
+ ecb_assume (current + size <= end);
+ }
+
+If you then call this function twice, like this:
+
+ reserve (10);
+ reserve (1);
+
+Then the compiler I<might> be able to optimise out the second call
+completely, as it knows that C<< current + 1 > end >> is false and the
+call will never be executed.
+
+=item ecb_unreachable ()
+
+This function does nothing itself, except tell the compiler that it will
+never be executed. Apart from suppressing a warning in some cases, this
+function can be used to implement C<ecb_assume> or similar functionality.
+
+=item ecb_prefetch (addr, rw, locality)
+
+Tells the compiler to try to prefetch memory at the given C<addr>ess
+for either reading (C<rw> = 0) or writing (C<rw> = 1). A C<locality> of
+C<0> means that there will only be one access later, C<3> means that
+the data will likely be accessed very often, and values in between mean
+something... in between. The memory pointed to by the address does not
+need to be accessible (it could be a null pointer for example), but C<rw>
+and C<locality> must be compile-time constants.
+
+This is a statement, not a function: you cannot use it as part of an
+expression.
+
+An obvious way to use this is to prefetch some data far away, in a big
+array you loop over. This prefetches memory some 128 array elements later,
+in the hope that it will be ready when the CPU arrives at that location.
+
+ int sum = 0;
+
+ for (i = 0; i < N; ++i)
+ {
+ sum += arr [i]
+ ecb_prefetch (arr + i + 128, 0, 0);
+ }
+
+It's hard to predict how far to prefetch, and most CPUs that can prefetch
+are often good enough to predict this kind of behaviour themselves. It
+gets more interesting with linked lists, especially when you do some fair
+processing on each list element:
+
+ for (node *n = start; n; n = n->next)
+ {
+ ecb_prefetch (n->next, 0, 0);
+ ... do medium amount of work with *n
+ }
+
+After processing the node, (part of) the next node might already be in
+cache.
+
+=back
+
+=head2 BIT FIDDLING / BIT WIZARDRY
+
+=over 4
+
+=item bool ecb_big_endian ()
+
+=item bool ecb_little_endian ()
+
+These two functions return true if the byte order is big endian
+(most-significant byte first) or little endian (least-significant byte
+first) respectively.
+
+On systems that are neither, their return values are unspecified.
+
+=item int ecb_ctz32 (uint32_t x)
+
+=item int ecb_ctz64 (uint64_t x)
+
+Returns the index of the least significant bit set in C<x> (or
+equivalently the number of bits set to 0 before the least significant bit
+set), starting from 0. If C<x> is 0 the result is undefined.
+
+For smaller types than C<uint32_t> you can safely use C<ecb_ctz32>.
+
+For example:
+
+ ecb_ctz32 (3) = 0
+ ecb_ctz32 (6) = 1
+
+=item bool ecb_is_pot32 (uint32_t x)
+
+=item bool ecb_is_pot64 (uint32_t x)
+
+Returns true iff C<x> is a power of two or C<x == 0>.
+
+For smaller types than C<uint32_t> you can safely use C<ecb_is_pot32>.
+
+=item int ecb_ld32 (uint32_t x)
+
+=item int ecb_ld64 (uint64_t x)
+
+Returns the index of the most significant bit set in C<x>, or the number
+of digits the number requires in binary (so that C<< 2**ld <= x <
+2**(ld+1) >>). If C<x> is 0 the result is undefined. A common use case is
+to compute the integer binary logarithm, i.e. C<floor (log2 (n))>, for
+example to see how many bits a certain number requires to be encoded.
+
+This function is similar to the "count leading zero bits" function, except
+that that one returns how many zero bits are "in front" of the number (in
+the given data type), while C<ecb_ld> returns how many bits the number
+itself requires.
+
+For smaller types than C<uint32_t> you can safely use C<ecb_ld32>.
+
+=item int ecb_popcount32 (uint32_t x)
+
+=item int ecb_popcount64 (uint64_t x)
+
+Returns the number of bits set to 1 in C<x>.
+
+For smaller types than C<uint32_t> you can safely use C<ecb_popcount32>.
+
+For example:
+
+ ecb_popcount32 (7) = 3
+ ecb_popcount32 (255) = 8
+
+=item uint8_t ecb_bitrev8 (uint8_t x)
+
+=item uint16_t ecb_bitrev16 (uint16_t x)
+
+=item uint32_t ecb_bitrev32 (uint32_t x)
+
+Reverses the bits in x, i.e. the MSB becomes the LSB, MSB-1 becomes LSB+1
+and so on.
+
+Example:
+
+ ecb_bitrev8 (0xa7) = 0xea
+ ecb_bitrev32 (0xffcc4411) = 0x882233ff
+
+=item uint32_t ecb_bswap16 (uint32_t x)
+
+=item uint32_t ecb_bswap32 (uint32_t x)
+
+=item uint64_t ecb_bswap64 (uint64_t x)
+
+These functions return the value of the 16-bit (32-bit, 64-bit) value
+C<x> after reversing the order of bytes (0x11223344 becomes 0x44332211 in
+C<ecb_bswap32>).
+
+=item uint8_t ecb_rotl8 (uint8_t x, unsigned int count)
+
+=item uint16_t ecb_rotl16 (uint16_t x, unsigned int count)
+
+=item uint32_t ecb_rotl32 (uint32_t x, unsigned int count)
+
+=item uint64_t ecb_rotl64 (uint64_t x, unsigned int count)
+
+=item uint8_t ecb_rotr8 (uint8_t x, unsigned int count)
+
+=item uint16_t ecb_rotr16 (uint16_t x, unsigned int count)
+
+=item uint32_t ecb_rotr32 (uint32_t x, unsigned int count)
+
+=item uint64_t ecb_rotr64 (uint64_t x, unsigned int count)
+
+These two families of functions return the value of C<x> after rotating
+all the bits by C<count> positions to the right (C<ecb_rotr>) or left
+(C<ecb_rotl>).
+
+Current GCC versions understand these functions and usually compile them
+to "optimal" code (e.g. a single C<rol> or a combination of C<shld> on
+x86).
+
+=back
+
+=head2 FLOATING POINT FIDDLING
+
+=over 4
+
+=item ECB_INFINITY [-UECB_NO_LIBM]
+
+Evaluates to positive infinity if supported by the platform, otherwise to
+a truly huge number.
+
+=item ECB_NAN [-UECB_NO_LIBM]
+
+Evaluates to a quiet NAN if supported by the platform, otherwise to
+C<ECB_INFINITY>.
+
+=item float ecb_ldexpf (float x, int exp) [-UECB_NO_LIBM]
+
+Same as C<ldexpf>, but always available.
+
+=item uint32_t ecb_float_to_binary16 (float x) [-UECB_NO_LIBM]
+
+=item uint32_t ecb_float_to_binary32 (float x) [-UECB_NO_LIBM]
+
+=item uint64_t ecb_double_to_binary64 (double x) [-UECB_NO_LIBM]
+
+These functions each take an argument in the native C<float> or C<double>
+type and return the IEEE 754 bit representation of it (binary16/half,
+binary32/single or binary64/double precision).
+
+The bit representation is just as IEEE 754 defines it, i.e. the sign bit
+will be the most significant bit, followed by exponent and mantissa.
+
+This function should work even when the native floating point format isn't
+IEEE compliant, of course at a speed and code size penalty, and of course
+also within reasonable limits (it tries to convert NaNs, infinities and
+denormals, but will likely convert negative zero to positive zero).
+
+On all modern platforms (where C<ECB_STDFP> is true), the compiler should
+be able to optimise away this function completely.
+
+These functions can be helpful when serialising floats to the network - you
+can serialise the return value like a normal uint16_t/uint32_t/uint64_t.
+
+Another use for these functions is to manipulate floating point values
+directly.
+
+Silly example: toggle the sign bit of a float.
+
+ /* On gcc-4.7 on amd64, */
+ /* this results in a single add instruction to toggle the bit, and 4 extra */
+ /* instructions to move the float value to an integer register and back. */
+
+ x = ecb_binary32_to_float (ecb_float_to_binary32 (x) ^ 0x80000000U)
+
+=item float ecb_binary16_to_float (uint16_t x) [-UECB_NO_LIBM]
+
+=item float ecb_binary32_to_float (uint32_t x) [-UECB_NO_LIBM]
+
+=item double ecb_binary64_to_double (uint64_t x) [-UECB_NO_LIBM]
+
+The reverse operation of the previous function - takes the bit
+representation of an IEEE binary16, binary32 or binary64 number (half,
+single or double precision) and converts it to the native C<float> or
+C<double> format.
+
+This function should work even when the native floating point format isn't
+IEEE compliant, of course at a speed and code size penalty, and of course
+also within reasonable limits (it tries to convert normals and denormals,
+and might be lucky for infinities, and with extraordinary luck, also for
+negative zero).
+
+On all modern platforms (where C<ECB_STDFP> is true), the compiler should
+be able to optimise away this function completely.
+
+=item uint16_t ecb_binary32_to_binary16 (uint32_t x)
+
+=item uint32_t ecb_binary16_to_binary32 (uint16_t x)
+
+Convert a IEEE binary32/single precision to binary16/half format, and vice
+versa, handling all details (round-to-nearest-even, subnormals, infinity
+and NaNs) correctly.
+
+These are functions are available under C<-DECB_NO_LIBM>, since
+they do not rely on the platform floating point format. The
+C<ecb_float_to_binary16> and C<ecb_binary16_to_float> functions are
+usually what you want.
+
+=back
+
+=head2 ARITHMETIC
+
+=over 4
+
+=item x = ecb_mod (m, n)
+
+Returns C<m> modulo C<n>, which is the same as the positive remainder
+of the division operation between C<m> and C<n>, using floored
+division. Unlike the C remainder operator C<%>, this function ensures that
+the return value is always positive and that the two numbers I<m> and
+I<m' = m + i * n> result in the same value modulo I<n> - in other words,
+C<ecb_mod> implements the mathematical modulo operation, which is missing
+in the language.
+
+C<n> must be strictly positive (i.e. C<< >= 1 >>), while C<m> must be
+negatable, that is, both C<m> and C<-m> must be representable in its
+type (this typically excludes the minimum signed integer value, the same
+limitation as for C</> and C<%> in C).
+
+Current GCC versions compile this into an efficient branchless sequence on
+almost all CPUs.
+
+For example, when you want to rotate forward through the members of an
+array for increasing C<m> (which might be negative), then you should use
+C<ecb_mod>, as the C<%> operator might give either negative results, or
+change direction for negative values:
+
+ for (m = -100; m <= 100; ++m)
+ int elem = myarray [ecb_mod (m, ecb_array_length (myarray))];
+
+=item x = ecb_div_rd (val, div)
+
+=item x = ecb_div_ru (val, div)
+
+Returns C<val> divided by C<div> rounded down or up, respectively.
+C<val> and C<div> must have integer types and C<div> must be strictly
+positive. Note that these functions are implemented with macros in C
+and with function templates in C++.
+
+=back
+
+=head2 UTILITY
+
+=over 4
+
+=item element_count = ecb_array_length (name)
+
+Returns the number of elements in the array C<name>. For example:
+
+ int primes[] = { 2, 3, 5, 7, 11 };
+ int sum = 0;
+
+ for (i = 0; i < ecb_array_length (primes); i++)
+ sum += primes [i];
+
+=back
+
+=head2 SYMBOLS GOVERNING COMPILATION OF ECB.H ITSELF
+
+These symbols need to be defined before including F<ecb.h> the first time.
+
+=over 4
+
+=item ECB_NO_THREADS
+
+If F<ecb.h> is never used from multiple threads, then this symbol can
+be defined, in which case memory fences (and similar constructs) are
+completely removed, leading to more efficient code and fewer dependencies.
+
+Setting this symbol to a true value implies C<ECB_NO_SMP>.
+
+=item ECB_NO_SMP
+
+The weaker version of C<ECB_NO_THREADS> - if F<ecb.h> is used from
+multiple threads, but never concurrently (e.g. if the system the program
+runs on has only a single CPU with a single core, no hyperthreading and so
+on), then this symbol can be defined, leading to more efficient code and
+fewer dependencies.
+
+=item ECB_NO_LIBM
+
+When defined to C<1>, do not export any functions that might introduce
+dependencies on the math library (usually called F<-lm>) - these are
+marked with [-UECB_NO_LIBM].
+
+=back
+
+=head1 UNDOCUMENTED FUNCTIONALITY
+
+F<ecb.h> is full of undocumented functionality as well, some of which is
+intended to be internal-use only, some of which we forgot to document, and
+some of which we hide because we are not sure we will keep the interface
+stable.
+
+While you are welcome to rummage around and use whatever you find useful
+(we can't stop you), keep in mind that we will change undocumented
+functionality in incompatible ways without thinking twice, while we are
+considerably more conservative with documented things.
+
+=head1 AUTHORS
+
+C<libecb> is designed and maintained by:
+
+ Emanuele Giaquinta <e.giaquinta@glauco.it>
+ Marc Alexander Lehmann <schmorp@schmorp.de>
+
+
--- rxvt-unicode/libecb/LICENSE
+++ rxvt-unicode/libecb/LICENSE
@@ -0,0 +1,37 @@
+All files in libecb are Copyright (C)2009-2011 Marc Alexander Lehmann and
+others (see individual files).
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above
+ copyright notice, this list of conditions and the following
+ disclaimer in the documentation and/or other materials provided
+ with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Alternatively, the contents of this package may be used under the terms
+of the GNU General Public License ("GPL") version 2 or any later version,
+in which case the provisions of the GPL are applicable instead of the
+above. If you wish to allow the use of your version of this package only
+under the terms of the GPL and not to allow others to use your version of
+this file under the BSD license, indicate your decision by deleting the
+provisions above and replace them with the notice and other provisions
+required by the GPL in this and the other files of this package. If you do
+not delete the provisions above, a recipient may use your version of this
+file under either the BSD or the GPL.
--- rxvt-unicode/libecb/README
+++ rxvt-unicode/libecb/README
@@ -0,0 +1,15 @@
+libecb - e compiler builtins
+
+This project delivers you many gcc builtins, attributes and a number of
+generally useful low-level functions, such as popcount, expect, prefetch,
+noinline, assume, unreachable and so on.
+
+The home of the library is:
+
+ http://software.schmorp.de/pkg/libecb
+
+Please refer to ecb.pod for more information, the latest version can be
+found here:
+
+ http://pod.tst.eu/http://cvs.schmorp.de/libecb/ecb.pod
+
--- rxvt-unicode/libev/autogen.sh
+++ rxvt-unicode/libev/autogen.sh
@@ -0,0 +1,3 @@
+#!/bin/sh
+
+autoreconf --install --symlink --force
--- rxvt-unicode/libev/Changes
+++ rxvt-unicode/libev/Changes
@@ -1,18 +1,18 @@
Revision history for libev, a high-performance and full-featured event loop.
-TODO: ev_loop_wakeup
-TODO: EV_STANDALONE == NO_HASSEL (do not use clock_gettime in ev_standalone)
-TODO: faq, process a thing in each iteration
-TODO: dbeugging tips, ev_verify, ev_init twice
-TODO: ev_break for immediate exit (EVBREAK_NOW?)
-TODO: ev_feed_child_event
-TODO: document the special problem of signals around fork.
-TODO: store pid for each signal
-TODO: document file descriptor usage per loop
-TODO: store loop pid_t and compare isndie signal handler,store 1 for same, 2 for differign pid, clean up in loop_fork
-TODO: embed watchers need updating when fd changes
-TODO: document portability requirements for atomic pointer access
-TODO: document requirements for function pointers and calling conventions.
+ - ANDROID => __ANDROID__ (reported by enh@google.com).
+ - disable epoll_create1 on android because it has broken header files
+ and google is unwilling to fix them (reported by enh@google.com).
+
+4.24 Wed Dec 28 05:19:55 CET 2016
+ - bump version to 4.24, as the release tarball inexplicably
+ didn't have the right version in ev.h, even though the cvs-tagged
+ version did have the right one (reported by Ales Teska).
+
+4.23 Wed Nov 16 18:23:41 CET 2016
+ - move some declarations at the beginning to help certain retarded
+ microsoft compilers, even though their documentation claims
+ otherwise (reported by Ruslan Osmanov).
4.22 Sun Dec 20 22:11:50 CET 2015
- when epoll detects unremovable fds in the fd set, rebuild
--- rxvt-unicode/libev/configure.ac
+++ rxvt-unicode/libev/configure.ac
@@ -0,0 +1,27 @@
+AC_INIT
+
+orig_CFLAGS="$CFLAGS"
+
+AC_CONFIG_SRCDIR([ev_epoll.c])
+
+dnl also update ev.h!
+AM_INIT_AUTOMAKE(libev,4.24)
+AC_CONFIG_HEADERS([config.h])
+AM_MAINTAINER_MODE
+
+AC_PROG_CC
+
+dnl Supply default CFLAGS, if not specified
+if test -z "$orig_CFLAGS"; then
+ if test x$GCC = xyes; then
+ CFLAGS="-g -O3"
+ fi
+fi
+
+AC_PROG_INSTALL
+AC_PROG_LIBTOOL
+
+m4_include([libev.m4])
+
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
--- rxvt-unicode/libev/ev.3
+++ rxvt-unicode/libev/ev.3
@@ -0,0 +1,5647 @@
+.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.29)
+.\"
+.\" Standard preamble:
+.\" ========================================================================
+.de Sp \" Vertical space (when we can't use .PP)
+.if t .sp .5v
+.if n .sp
+..
+.de Vb \" Begin verbatim text
+.ft CW
+.nf
+.ne \\$1
+..
+.de Ve \" End verbatim text
+.ft R
+.fi
+..
+.\" Set up some character translations and predefined strings. \*(-- will
+.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
+.\" double quote, and \*(R" will give a right double quote. \*(C+ will
+.\" give a nicer C++. Capital omega is used to do unbreakable dashes and
+.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
+.\" nothing in troff, for use with C<>.
+.tr \(*W-
+.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
+.ie n \{\
+. ds -- \(*W-
+. ds PI pi
+. if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
+. if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch
+. ds L" ""
+. ds R" ""
+. ds C` ""
+. ds C' ""
+'br\}
+.el\{\
+. ds -- \|\(em\|
+. ds PI \(*p
+. ds L" ``
+. ds R" ''
+. ds C`
+. ds C'
+'br\}
+.\"
+.\" Escape single quotes in literal strings from groff's Unicode transform.
+.ie \n(.g .ds Aq \(aq
+.el .ds Aq '
+.\"
+.\" If the F register is turned on, we'll generate index entries on stderr for
+.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
+.\" entries marked with X<> in POD. Of course, you'll have to process the
+.\" output yourself in some meaningful fashion.
+.\"
+.\" Avoid warning from groff about undefined register 'F'.
+.de IX
+..
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+..
+. if !\nF==2 \{
+. nr % 0
+. nr F 2
+. \}
+. \}
+.\}
+.rr rF
+.\"
+.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
+.\" Fear. Run. Save yourself. No user-serviceable parts.
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+. ds #H ((1u-(\\\\n(.fu%2u))*.13m)
+. ds #V .6m
+. ds #F 0
+. ds #[ \&
+. ds #] \&
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+. \" simple accents for nroff and troff
+.if n \{\
+. ds ' \&
+. ds ` \&
+. ds ^ \&
+. ds , \&
+. ds ~ ~
+. ds /
+.\}
+.if t \{\
+. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
+. ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
+. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
+. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
+. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
+. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
+.\}
+. \" troff and (daisy-wheel) nroff accents
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+.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
+.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
+.ds ae a\h'-(\w'a'u*4/10)'e
+.ds Ae A\h'-(\w'A'u*4/10)'E
+. \" corrections for vroff
+.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
+.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
+. \" for low resolution devices (crt and lpr)
+.if \n(.H>23 .if \n(.V>19 \
+\{\
+. ds : e
+. ds 8 ss
+. ds o a
+. ds d- d\h'-1'\(ga
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+. ds Th \o'LP'
+. ds ae ae
+. ds Ae AE
+.\}
+.rm #[ #] #H #V #F C
+.\" ========================================================================
+.\"
+.IX Title "LIBEV 3"
+.TH LIBEV 3 "2017-06-21" "libev-4.24" "libev - high performance full featured event loop"
+.\" For nroff, turn off justification. Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+.nh
+.SH "NAME"
+libev \- a high performance full\-featured event loop written in C
+.SH "SYNOPSIS"
+.IX Header "SYNOPSIS"
+.Vb 1
+\& #include <ev.h>
+.Ve
+.SS "\s-1EXAMPLE PROGRAM\s0"
+.IX Subsection "EXAMPLE PROGRAM"
+.Vb 2
+\& // a single header file is required
+\& #include <ev.h>
+\&
+\& #include <stdio.h> // for puts
+\&
+\& // every watcher type has its own typedef\*(Aqd struct
+\& // with the name ev_TYPE
+\& ev_io stdin_watcher;
+\& ev_timer timeout_watcher;
+\&
+\& // all watcher callbacks have a similar signature
+\& // this callback is called when data is readable on stdin
+\& static void
+\& stdin_cb (EV_P_ ev_io *w, int revents)
+\& {
+\& puts ("stdin ready");
+\& // for one\-shot events, one must manually stop the watcher
+\& // with its corresponding stop function.
+\& ev_io_stop (EV_A_ w);
+\&
+\& // this causes all nested ev_run\*(Aqs to stop iterating
+\& ev_break (EV_A_ EVBREAK_ALL);
+\& }
+\&
+\& // another callback, this time for a time\-out
+\& static void
+\& timeout_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& puts ("timeout");
+\& // this causes the innermost ev_run to stop iterating
+\& ev_break (EV_A_ EVBREAK_ONE);
+\& }
+\&
+\& int
+\& main (void)
+\& {
+\& // use the default event loop unless you have special needs
+\& struct ev_loop *loop = EV_DEFAULT;
+\&
+\& // initialise an io watcher, then start it
+\& // this one will watch for stdin to become readable
+\& ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
+\& ev_io_start (loop, &stdin_watcher);
+\&
+\& // initialise a timer watcher, then start it
+\& // simple non\-repeating 5.5 second timeout
+\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+\& ev_timer_start (loop, &timeout_watcher);
+\&
+\& // now wait for events to arrive
+\& ev_run (loop, 0);
+\&
+\& // break was called, so exit
+\& return 0;
+\& }
+.Ve
+.SH "ABOUT THIS DOCUMENT"
+.IX Header "ABOUT THIS DOCUMENT"
+This document documents the libev software package.
+.PP
+The newest version of this document is also available as an html-formatted
+web page you might find easier to navigate when reading it for the first
+time: <http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>.
+.PP
+While this document tries to be as complete as possible in documenting
+libev, its usage and the rationale behind its design, it is not a tutorial
+on event-based programming, nor will it introduce event-based programming
+with libev.
+.PP
+Familiarity with event based programming techniques in general is assumed
+throughout this document.
+.SH "WHAT TO READ WHEN IN A HURRY"
+.IX Header "WHAT TO READ WHEN IN A HURRY"
+This manual tries to be very detailed, but unfortunately, this also makes
+it very long. If you just want to know the basics of libev, I suggest
+reading \*(L"\s-1ANATOMY OF A WATCHER\*(R"\s0, then the \*(L"\s-1EXAMPLE PROGRAM\*(R"\s0 above and
+look up the missing functions in \*(L"\s-1GLOBAL FUNCTIONS\*(R"\s0 and the \f(CW\*(C`ev_io\*(C'\fR and
+\&\f(CW\*(C`ev_timer\*(C'\fR sections in \*(L"\s-1WATCHER TYPES\*(R"\s0.
+.SH "ABOUT LIBEV"
+.IX Header "ABOUT LIBEV"
+Libev is an event loop: you register interest in certain events (such as a
+file descriptor being readable or a timeout occurring), and it will manage
+these event sources and provide your program with events.
+.PP
+To do this, it must take more or less complete control over your process
+(or thread) by executing the \fIevent loop\fR handler, and will then
+communicate events via a callback mechanism.
+.PP
+You register interest in certain events by registering so-called \fIevent
+watchers\fR, which are relatively small C structures you initialise with the
+details of the event, and then hand it over to libev by \fIstarting\fR the
+watcher.
+.SS "\s-1FEATURES\s0"
+.IX Subsection "FEATURES"
+Libev supports \f(CW\*(C`select\*(C'\fR, \f(CW\*(C`poll\*(C'\fR, the Linux-specific \f(CW\*(C`epoll\*(C'\fR, the
+BSD-specific \f(CW\*(C`kqueue\*(C'\fR and the Solaris-specific event port mechanisms
+for file descriptor events (\f(CW\*(C`ev_io\*(C'\fR), the Linux \f(CW\*(C`inotify\*(C'\fR interface
+(for \f(CW\*(C`ev_stat\*(C'\fR), Linux eventfd/signalfd (for faster and cleaner
+inter-thread wakeup (\f(CW\*(C`ev_async\*(C'\fR)/signal handling (\f(CW\*(C`ev_signal\*(C'\fR)) relative
+timers (\f(CW\*(C`ev_timer\*(C'\fR), absolute timers with customised rescheduling
+(\f(CW\*(C`ev_periodic\*(C'\fR), synchronous signals (\f(CW\*(C`ev_signal\*(C'\fR), process status
+change events (\f(CW\*(C`ev_child\*(C'\fR), and event watchers dealing with the event
+loop mechanism itself (\f(CW\*(C`ev_idle\*(C'\fR, \f(CW\*(C`ev_embed\*(C'\fR, \f(CW\*(C`ev_prepare\*(C'\fR and
+\&\f(CW\*(C`ev_check\*(C'\fR watchers) as well as file watchers (\f(CW\*(C`ev_stat\*(C'\fR) and even
+limited support for fork events (\f(CW\*(C`ev_fork\*(C'\fR).
+.PP
+It also is quite fast (see this
+benchmark <http://libev.schmorp.de/bench.html> comparing it to libevent
+for example).
+.SS "\s-1CONVENTIONS\s0"
+.IX Subsection "CONVENTIONS"
+Libev is very configurable. In this manual the default (and most common)
+configuration will be described, which supports multiple event loops. For
+more info about various configuration options please have a look at
+\&\fB\s-1EMBED\s0\fR section in this manual. If libev was configured without support
+for multiple event loops, then all functions taking an initial argument of
+name \f(CW\*(C`loop\*(C'\fR (which is always of type \f(CW\*(C`struct ev_loop *\*(C'\fR) will not have
+this argument.
+.SS "\s-1TIME REPRESENTATION\s0"
+.IX Subsection "TIME REPRESENTATION"
+Libev represents time as a single floating point number, representing
+the (fractional) number of seconds since the (\s-1POSIX\s0) epoch (in practice
+somewhere near the beginning of 1970, details are complicated, don't
+ask). This type is called \f(CW\*(C`ev_tstamp\*(C'\fR, which is what you should use
+too. It usually aliases to the \f(CW\*(C`double\*(C'\fR type in C. When you need to do
+any calculations on it, you should treat it as some floating point value.
+.PP
+Unlike the name component \f(CW\*(C`stamp\*(C'\fR might indicate, it is also used for
+time differences (e.g. delays) throughout libev.
+.SH "ERROR HANDLING"
+.IX Header "ERROR HANDLING"
+Libev knows three classes of errors: operating system errors, usage errors
+and internal errors (bugs).
+.PP
+When libev catches an operating system error it cannot handle (for example
+a system call indicating a condition libev cannot fix), it calls the callback
+set via \f(CW\*(C`ev_set_syserr_cb\*(C'\fR, which is supposed to fix the problem or
+abort. The default is to print a diagnostic message and to call \f(CW\*(C`abort
+()\*(C'\fR.
+.PP
+When libev detects a usage error such as a negative timer interval, then
+it will print a diagnostic message and abort (via the \f(CW\*(C`assert\*(C'\fR mechanism,
+so \f(CW\*(C`NDEBUG\*(C'\fR will disable this checking): these are programming errors in
+the libev caller and need to be fixed there.
+.PP
+Libev also has a few internal error-checking \f(CW\*(C`assert\*(C'\fRions, and also has
+extensive consistency checking code. These do not trigger under normal
+circumstances, as they indicate either a bug in libev or worse.
+.SH "GLOBAL FUNCTIONS"
+.IX Header "GLOBAL FUNCTIONS"
+These functions can be called anytime, even before initialising the
+library in any way.
+.IP "ev_tstamp ev_time ()" 4
+.IX Item "ev_tstamp ev_time ()"
+Returns the current time as libev would use it. Please note that the
+\&\f(CW\*(C`ev_now\*(C'\fR function is usually faster and also often returns the timestamp
+you actually want to know. Also interesting is the combination of
+\&\f(CW\*(C`ev_now_update\*(C'\fR and \f(CW\*(C`ev_now\*(C'\fR.
+.IP "ev_sleep (ev_tstamp interval)" 4
+.IX Item "ev_sleep (ev_tstamp interval)"
+Sleep for the given interval: The current thread will be blocked
+until either it is interrupted or the given time interval has
+passed (approximately \- it might return a bit earlier even if not
+interrupted). Returns immediately if \f(CW\*(C`interval <= 0\*(C'\fR.
+.Sp
+Basically this is a sub-second-resolution \f(CW\*(C`sleep ()\*(C'\fR.
+.Sp
+The range of the \f(CW\*(C`interval\*(C'\fR is limited \- libev only guarantees to work
+with sleep times of up to one day (\f(CW\*(C`interval <= 86400\*(C'\fR).
+.IP "int ev_version_major ()" 4
+.IX Item "int ev_version_major ()"
+.PD 0
+.IP "int ev_version_minor ()" 4
+.IX Item "int ev_version_minor ()"
+.PD
+You can find out the major and minor \s-1ABI\s0 version numbers of the library
+you linked against by calling the functions \f(CW\*(C`ev_version_major\*(C'\fR and
+\&\f(CW\*(C`ev_version_minor\*(C'\fR. If you want, you can compare against the global
+symbols \f(CW\*(C`EV_VERSION_MAJOR\*(C'\fR and \f(CW\*(C`EV_VERSION_MINOR\*(C'\fR, which specify the
+version of the library your program was compiled against.
+.Sp
+These version numbers refer to the \s-1ABI\s0 version of the library, not the
+release version.
+.Sp
+Usually, it's a good idea to terminate if the major versions mismatch,
+as this indicates an incompatible change. Minor versions are usually
+compatible to older versions, so a larger minor version alone is usually
+not a problem.
+.Sp
+Example: Make sure we haven't accidentally been linked against the wrong
+version (note, however, that this will not detect other \s-1ABI\s0 mismatches,
+such as \s-1LFS\s0 or reentrancy).
+.Sp
+.Vb 3
+\& assert (("libev version mismatch",
+\& ev_version_major () == EV_VERSION_MAJOR
+\& && ev_version_minor () >= EV_VERSION_MINOR));
+.Ve
+.IP "unsigned int ev_supported_backends ()" 4
+.IX Item "unsigned int ev_supported_backends ()"
+Return the set of all backends (i.e. their corresponding \f(CW\*(C`EV_BACKEND_*\*(C'\fR
+value) compiled into this binary of libev (independent of their
+availability on the system you are running on). See \f(CW\*(C`ev_default_loop\*(C'\fR for
+a description of the set values.
+.Sp
+Example: make sure we have the epoll method, because yeah this is cool and
+a must have and can we have a torrent of it please!!!11
+.Sp
+.Vb 2
+\& assert (("sorry, no epoll, no sex",
+\& ev_supported_backends () & EVBACKEND_EPOLL));
+.Ve
+.IP "unsigned int ev_recommended_backends ()" 4
+.IX Item "unsigned int ev_recommended_backends ()"
+Return the set of all backends compiled into this binary of libev and
+also recommended for this platform, meaning it will work for most file
+descriptor types. This set is often smaller than the one returned by
+\&\f(CW\*(C`ev_supported_backends\*(C'\fR, as for example kqueue is broken on most BSDs
+and will not be auto-detected unless you explicitly request it (assuming
+you know what you are doing). This is the set of backends that libev will
+probe for if you specify no backends explicitly.
+.IP "unsigned int ev_embeddable_backends ()" 4
+.IX Item "unsigned int ev_embeddable_backends ()"
+Returns the set of backends that are embeddable in other event loops. This
+value is platform-specific but can include backends not available on the
+current system. To find which embeddable backends might be supported on
+the current system, you would need to look at \f(CW\*(C`ev_embeddable_backends ()
+& ev_supported_backends ()\*(C'\fR, likewise for recommended ones.
+.Sp
+See the description of \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
+.IP "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())" 4
+.IX Item "ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())"
+Sets the allocation function to use (the prototype is similar \- the
+semantics are identical to the \f(CW\*(C`realloc\*(C'\fR C89/SuS/POSIX function). It is
+used to allocate and free memory (no surprises here). If it returns zero
+when memory needs to be allocated (\f(CW\*(C`size != 0\*(C'\fR), the library might abort
+or take some potentially destructive action.
+.Sp
+Since some systems (at least OpenBSD and Darwin) fail to implement
+correct \f(CW\*(C`realloc\*(C'\fR semantics, libev will use a wrapper around the system
+\&\f(CW\*(C`realloc\*(C'\fR and \f(CW\*(C`free\*(C'\fR functions by default.
+.Sp
+You could override this function in high-availability programs to, say,
+free some memory if it cannot allocate memory, to use a special allocator,
+or even to sleep a while and retry until some memory is available.
+.Sp
+Example: Replace the libev allocator with one that waits a bit and then
+retries (example requires a standards-compliant \f(CW\*(C`realloc\*(C'\fR).
+.Sp
+.Vb 6
+\& static void *
+\& persistent_realloc (void *ptr, size_t size)
+\& {
+\& for (;;)
+\& {
+\& void *newptr = realloc (ptr, size);
+\&
+\& if (newptr)
+\& return newptr;
+\&
+\& sleep (60);
+\& }
+\& }
+\&
+\& ...
+\& ev_set_allocator (persistent_realloc);
+.Ve
+.IP "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())" 4
+.IX Item "ev_set_syserr_cb (void (*cb)(const char *msg) throw ())"
+Set the callback function to call on a retryable system call error (such
+as failed select, poll, epoll_wait). The message is a printable string
+indicating the system call or subsystem causing the problem. If this
+callback is set, then libev will expect it to remedy the situation, no
+matter what, when it returns. That is, libev will generally retry the
+requested operation, or, if the condition doesn't go away, do bad stuff
+(such as abort).
+.Sp
+Example: This is basically the same thing that libev does internally, too.
+.Sp
+.Vb 6
+\& static void
+\& fatal_error (const char *msg)
+\& {
+\& perror (msg);
+\& abort ();
+\& }
+\&
+\& ...
+\& ev_set_syserr_cb (fatal_error);
+.Ve
+.IP "ev_feed_signal (int signum)" 4
+.IX Item "ev_feed_signal (int signum)"
+This function can be used to \*(L"simulate\*(R" a signal receive. It is completely
+safe to call this function at any time, from any context, including signal
+handlers or random threads.
+.Sp
+Its main use is to customise signal handling in your process, especially
+in the presence of threads. For example, you could block signals
+by default in all threads (and specifying \f(CW\*(C`EVFLAG_NOSIGMASK\*(C'\fR when
+creating any loops), and in one thread, use \f(CW\*(C`sigwait\*(C'\fR or any other
+mechanism to wait for signals, then \*(L"deliver\*(R" them to libev by calling
+\&\f(CW\*(C`ev_feed_signal\*(C'\fR.
+.SH "FUNCTIONS CONTROLLING EVENT LOOPS"
+.IX Header "FUNCTIONS CONTROLLING EVENT LOOPS"
+An event loop is described by a \f(CW\*(C`struct ev_loop *\*(C'\fR (the \f(CW\*(C`struct\*(C'\fR is
+\&\fInot\fR optional in this case unless libev 3 compatibility is disabled, as
+libev 3 had an \f(CW\*(C`ev_loop\*(C'\fR function colliding with the struct name).
+.PP
+The library knows two types of such loops, the \fIdefault\fR loop, which
+supports child process events, and dynamically created event loops which
+do not.
+.IP "struct ev_loop *ev_default_loop (unsigned int flags)" 4
+.IX Item "struct ev_loop *ev_default_loop (unsigned int flags)"
+This returns the \*(L"default\*(R" event loop object, which is what you should
+normally use when you just need \*(L"the event loop\*(R". Event loop objects and
+the \f(CW\*(C`flags\*(C'\fR parameter are described in more detail in the entry for
+\&\f(CW\*(C`ev_loop_new\*(C'\fR.
+.Sp
+If the default loop is already initialised then this function simply
+returns it (and ignores the flags. If that is troubling you, check
+\&\f(CW\*(C`ev_backend ()\*(C'\fR afterwards). Otherwise it will create it with the given
+flags, which should almost always be \f(CW0\fR, unless the caller is also the
+one calling \f(CW\*(C`ev_run\*(C'\fR or otherwise qualifies as \*(L"the main program\*(R".
+.Sp
+If you don't know what event loop to use, use the one returned from this
+function (or via the \f(CW\*(C`EV_DEFAULT\*(C'\fR macro).
+.Sp
+Note that this function is \fInot\fR thread-safe, so if you want to use it
+from multiple threads, you have to employ some kind of mutex (note also
+that this case is unlikely, as loops cannot be shared easily between
+threads anyway).
+.Sp
+The default loop is the only loop that can handle \f(CW\*(C`ev_child\*(C'\fR watchers,
+and to do this, it always registers a handler for \f(CW\*(C`SIGCHLD\*(C'\fR. If this is
+a problem for your application you can either create a dynamic loop with
+\&\f(CW\*(C`ev_loop_new\*(C'\fR which doesn't do that, or you can simply overwrite the
+\&\f(CW\*(C`SIGCHLD\*(C'\fR signal handler \fIafter\fR calling \f(CW\*(C`ev_default_init\*(C'\fR.
+.Sp
+Example: This is the most typical usage.
+.Sp
+.Vb 2
+\& if (!ev_default_loop (0))
+\& fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
+.Ve
+.Sp
+Example: Restrict libev to the select and poll backends, and do not allow
+environment settings to be taken into account:
+.Sp
+.Vb 1
+\& ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
+.Ve
+.IP "struct ev_loop *ev_loop_new (unsigned int flags)" 4
+.IX Item "struct ev_loop *ev_loop_new (unsigned int flags)"
+This will create and initialise a new event loop object. If the loop
+could not be initialised, returns false.
+.Sp
+This function is thread-safe, and one common way to use libev with
+threads is indeed to create one loop per thread, and using the default
+loop in the \*(L"main\*(R" or \*(L"initial\*(R" thread.
+.Sp
+The flags argument can be used to specify special behaviour or specific
+backends to use, and is usually specified as \f(CW0\fR (or \f(CW\*(C`EVFLAG_AUTO\*(C'\fR).
+.Sp
+The following flags are supported:
+.RS 4
+.ie n .IP """EVFLAG_AUTO""" 4
+.el .IP "\f(CWEVFLAG_AUTO\fR" 4
+.IX Item "EVFLAG_AUTO"
+The default flags value. Use this if you have no clue (it's the right
+thing, believe me).
+.ie n .IP """EVFLAG_NOENV""" 4
+.el .IP "\f(CWEVFLAG_NOENV\fR" 4
+.IX Item "EVFLAG_NOENV"
+If this flag bit is or'ed into the flag value (or the program runs setuid
+or setgid) then libev will \fInot\fR look at the environment variable
+\&\f(CW\*(C`LIBEV_FLAGS\*(C'\fR. Otherwise (the default), this environment variable will
+override the flags completely if it is found in the environment. This is
+useful to try out specific backends to test their performance, to work
+around bugs, or to make libev threadsafe (accessing environment variables
+cannot be done in a threadsafe way, but usually it works if no other
+thread modifies them).
+.ie n .IP """EVFLAG_FORKCHECK""" 4
+.el .IP "\f(CWEVFLAG_FORKCHECK\fR" 4
+.IX Item "EVFLAG_FORKCHECK"
+Instead of calling \f(CW\*(C`ev_loop_fork\*(C'\fR manually after a fork, you can also
+make libev check for a fork in each iteration by enabling this flag.
+.Sp
+This works by calling \f(CW\*(C`getpid ()\*(C'\fR on every iteration of the loop,
+and thus this might slow down your event loop if you do a lot of loop
+iterations and little real work, but is usually not noticeable (on my
+GNU/Linux system for example, \f(CW\*(C`getpid\*(C'\fR is actually a simple 5\-insn sequence
+without a system call and thus \fIvery\fR fast, but my GNU/Linux system also has
+\&\f(CW\*(C`pthread_atfork\*(C'\fR which is even faster).
+.Sp
+The big advantage of this flag is that you can forget about fork (and
+forget about forgetting to tell libev about forking, although you still
+have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR) when you use this flag.
+.Sp
+This flag setting cannot be overridden or specified in the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR
+environment variable.
+.ie n .IP """EVFLAG_NOINOTIFY""" 4
+.el .IP "\f(CWEVFLAG_NOINOTIFY\fR" 4
+.IX Item "EVFLAG_NOINOTIFY"
+When this flag is specified, then libev will not attempt to use the
+\&\fIinotify\fR \s-1API\s0 for its \f(CW\*(C`ev_stat\*(C'\fR watchers. Apart from debugging and
+testing, this flag can be useful to conserve inotify file descriptors, as
+otherwise each loop using \f(CW\*(C`ev_stat\*(C'\fR watchers consumes one inotify handle.
+.ie n .IP """EVFLAG_SIGNALFD""" 4
+.el .IP "\f(CWEVFLAG_SIGNALFD\fR" 4
+.IX Item "EVFLAG_SIGNALFD"
+When this flag is specified, then libev will attempt to use the
+\&\fIsignalfd\fR \s-1API\s0 for its \f(CW\*(C`ev_signal\*(C'\fR (and \f(CW\*(C`ev_child\*(C'\fR) watchers. This \s-1API\s0
+delivers signals synchronously, which makes it both faster and might make
+it possible to get the queued signal data. It can also simplify signal
+handling with threads, as long as you properly block signals in your
+threads that are not interested in handling them.
+.Sp
+Signalfd will not be used by default as this changes your signal mask, and
+there are a lot of shoddy libraries and programs (glib's threadpool for
+example) that can't properly initialise their signal masks.
+.ie n .IP """EVFLAG_NOSIGMASK""" 4
+.el .IP "\f(CWEVFLAG_NOSIGMASK\fR" 4
+.IX Item "EVFLAG_NOSIGMASK"
+When this flag is specified, then libev will avoid to modify the signal
+mask. Specifically, this means you have to make sure signals are unblocked
+when you want to receive them.
+.Sp
+This behaviour is useful when you want to do your own signal handling, or
+want to handle signals only in specific threads and want to avoid libev
+unblocking the signals.
+.Sp
+It's also required by \s-1POSIX\s0 in a threaded program, as libev calls
+\&\f(CW\*(C`sigprocmask\*(C'\fR, whose behaviour is officially unspecified.
+.Sp
+This flag's behaviour will become the default in future versions of libev.
+.ie n .IP """EVBACKEND_SELECT"" (value 1, portable select backend)" 4
+.el .IP "\f(CWEVBACKEND_SELECT\fR (value 1, portable select backend)" 4
+.IX Item "EVBACKEND_SELECT (value 1, portable select backend)"
+This is your standard \fIselect\fR\|(2) backend. Not \fIcompletely\fR standard, as
+libev tries to roll its own fd_set with no limits on the number of fds,
+but if that fails, expect a fairly low limit on the number of fds when
+using this backend. It doesn't scale too well (O(highest_fd)), but its
+usually the fastest backend for a low number of (low-numbered :) fds.
+.Sp
+To get good performance out of this backend you need a high amount of
+parallelism (most of the file descriptors should be busy). If you are
+writing a server, you should \f(CW\*(C`accept ()\*(C'\fR in a loop to accept as many
+connections as possible during one iteration. You might also want to have
+a look at \f(CW\*(C`ev_set_io_collect_interval ()\*(C'\fR to increase the amount of
+readiness notifications you get per iteration.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR to the \f(CW\*(C`readfds\*(C'\fR set and \f(CW\*(C`EV_WRITE\*(C'\fR to the
+\&\f(CW\*(C`writefds\*(C'\fR set (and to work around Microsoft Windows bugs, also onto the
+\&\f(CW\*(C`exceptfds\*(C'\fR set on that platform).
+.ie n .IP """EVBACKEND_POLL"" (value 2, poll backend, available everywhere except on windows)" 4
+.el .IP "\f(CWEVBACKEND_POLL\fR (value 2, poll backend, available everywhere except on windows)" 4
+.IX Item "EVBACKEND_POLL (value 2, poll backend, available everywhere except on windows)"
+And this is your standard \fIpoll\fR\|(2) backend. It's more complicated
+than select, but handles sparse fds better and has no artificial
+limit on the number of fds you can use (except it will slow down
+considerably with a lot of inactive fds). It scales similarly to select,
+i.e. O(total_fds). See the entry for \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR, above, for
+performance tips.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR to \f(CW\*(C`POLLIN | POLLERR | POLLHUP\*(C'\fR, and
+\&\f(CW\*(C`EV_WRITE\*(C'\fR to \f(CW\*(C`POLLOUT | POLLERR | POLLHUP\*(C'\fR.
+.ie n .IP """EVBACKEND_EPOLL"" (value 4, Linux)" 4
+.el .IP "\f(CWEVBACKEND_EPOLL\fR (value 4, Linux)" 4
+.IX Item "EVBACKEND_EPOLL (value 4, Linux)"
+Use the linux-specific \fIepoll\fR\|(7) interface (for both pre\- and post\-2.6.9
+kernels).
+.Sp
+For few fds, this backend is a bit little slower than poll and select, but
+it scales phenomenally better. While poll and select usually scale like
+O(total_fds) where total_fds is the total number of fds (or the highest
+fd), epoll scales either O(1) or O(active_fds).
+.Sp
+The epoll mechanism deserves honorable mention as the most misdesigned
+of the more advanced event mechanisms: mere annoyances include silently
+dropping file descriptors, requiring a system call per change per file
+descriptor (and unnecessary guessing of parameters), problems with dup,
+returning before the timeout value, resulting in additional iterations
+(and only giving 5ms accuracy while select on the same platform gives
+0.1ms) and so on. The biggest issue is fork races, however \- if a program
+forks then \fIboth\fR parent and child process have to recreate the epoll
+set, which can take considerable time (one syscall per file descriptor)
+and is of course hard to detect.
+.Sp
+Epoll is also notoriously buggy \- embedding epoll fds \fIshould\fR work,
+but of course \fIdoesn't\fR, and epoll just loves to report events for
+totally \fIdifferent\fR file descriptors (even already closed ones, so
+one cannot even remove them from the set) than registered in the set
+(especially on \s-1SMP\s0 systems). Libev tries to counter these spurious
+notifications by employing an additional generation counter and comparing
+that against the events to filter out spurious ones, recreating the set
+when required. Epoll also erroneously rounds down timeouts, but gives you
+no way to know when and by how much, so sometimes you have to busy-wait
+because epoll returns immediately despite a nonzero timeout. And last
+not least, it also refuses to work with some file descriptors which work
+perfectly fine with \f(CW\*(C`select\*(C'\fR (files, many character devices...).
+.Sp
+Epoll is truly the train wreck among event poll mechanisms, a frankenpoll,
+cobbled together in a hurry, no thought to design or interaction with
+others. Oh, the pain, will it ever stop...
+.Sp
+While stopping, setting and starting an I/O watcher in the same iteration
+will result in some caching, there is still a system call per such
+incident (because the same \fIfile descriptor\fR could point to a different
+\&\fIfile description\fR now), so its best to avoid that. Also, \f(CW\*(C`dup ()\*(C'\fR'ed
+file descriptors might not work very well if you register events for both
+file descriptors.
+.Sp
+Best performance from this backend is achieved by not unregistering all
+watchers for a file descriptor until it has been closed, if possible,
+i.e. keep at least one watcher active per fd at all times. Stopping and
+starting a watcher (without re-setting it) also usually doesn't cause
+extra overhead. A fork can both result in spurious notifications as well
+as in libev having to destroy and recreate the epoll object, which can
+take considerable time and thus should be avoided.
+.Sp
+All this means that, in practice, \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR can be as fast or
+faster than epoll for maybe up to a hundred file descriptors, depending on
+the usage. So sad.
+.Sp
+While nominally embeddable in other event loops, this feature is broken in
+all kernel versions tested so far.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as
+\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.ie n .IP """EVBACKEND_KQUEUE"" (value 8, most \s-1BSD\s0 clones)" 4
+.el .IP "\f(CWEVBACKEND_KQUEUE\fR (value 8, most \s-1BSD\s0 clones)" 4
+.IX Item "EVBACKEND_KQUEUE (value 8, most BSD clones)"
+Kqueue deserves special mention, as at the time of this writing, it
+was broken on all BSDs except NetBSD (usually it doesn't work reliably
+with anything but sockets and pipes, except on Darwin, where of course
+it's completely useless). Unlike epoll, however, whose brokenness
+is by design, these kqueue bugs can (and eventually will) be fixed
+without \s-1API\s0 changes to existing programs. For this reason it's not being
+\&\*(L"auto-detected\*(R" unless you explicitly specify it in the flags (i.e. using
+\&\f(CW\*(C`EVBACKEND_KQUEUE\*(C'\fR) or libev was compiled on a known-to-be-good (\-enough)
+system like NetBSD.
+.Sp
+You still can embed kqueue into a normal poll or select backend and use it
+only for sockets (after having made sure that sockets work with kqueue on
+the target platform). See \f(CW\*(C`ev_embed\*(C'\fR watchers for more info.
+.Sp
+It scales in the same way as the epoll backend, but the interface to the
+kernel is more efficient (which says nothing about its actual speed, of
+course). While stopping, setting and starting an I/O watcher does never
+cause an extra system call as with \f(CW\*(C`EVBACKEND_EPOLL\*(C'\fR, it still adds up to
+two event changes per incident. Support for \f(CW\*(C`fork ()\*(C'\fR is very bad (you
+might have to leak fd's on fork, but it's more sane than epoll) and it
+drops fds silently in similarly hard-to-detect cases.
+.Sp
+This backend usually performs well under most conditions.
+.Sp
+While nominally embeddable in other event loops, this doesn't work
+everywhere, so you might need to test for this. And since it is broken
+almost everywhere, you should only use it when you have a lot of sockets
+(for which it usually works), by embedding it into another event loop
+(e.g. \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR (but \f(CW\*(C`poll\*(C'\fR is of course
+also broken on \s-1OS X\s0)) and, did I mention it, using it only for sockets.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR into an \f(CW\*(C`EVFILT_READ\*(C'\fR kevent with
+\&\f(CW\*(C`NOTE_EOF\*(C'\fR, and \f(CW\*(C`EV_WRITE\*(C'\fR into an \f(CW\*(C`EVFILT_WRITE\*(C'\fR kevent with
+\&\f(CW\*(C`NOTE_EOF\*(C'\fR.
+.ie n .IP """EVBACKEND_DEVPOLL"" (value 16, Solaris 8)" 4
+.el .IP "\f(CWEVBACKEND_DEVPOLL\fR (value 16, Solaris 8)" 4
+.IX Item "EVBACKEND_DEVPOLL (value 16, Solaris 8)"
+This is not implemented yet (and might never be, unless you send me an
+implementation). According to reports, \f(CW\*(C`/dev/poll\*(C'\fR only supports sockets
+and is not embeddable, which would limit the usefulness of this backend
+immensely.
+.ie n .IP """EVBACKEND_PORT"" (value 32, Solaris 10)" 4
+.el .IP "\f(CWEVBACKEND_PORT\fR (value 32, Solaris 10)" 4
+.IX Item "EVBACKEND_PORT (value 32, Solaris 10)"
+This uses the Solaris 10 event port mechanism. As with everything on Solaris,
+it's really slow, but it still scales very well (O(active_fds)).
+.Sp
+While this backend scales well, it requires one system call per active
+file descriptor per loop iteration. For small and medium numbers of file
+descriptors a \*(L"slow\*(R" \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR backend
+might perform better.
+.Sp
+On the positive side, this backend actually performed fully to
+specification in all tests and is fully embeddable, which is a rare feat
+among the OS-specific backends (I vastly prefer correctness over speed
+hacks).
+.Sp
+On the negative side, the interface is \fIbizarre\fR \- so bizarre that
+even sun itself gets it wrong in their code examples: The event polling
+function sometimes returns events to the caller even though an error
+occurred, but with no indication whether it has done so or not (yes, it's
+even documented that way) \- deadly for edge-triggered interfaces where you
+absolutely have to know whether an event occurred or not because you have
+to re-arm the watcher.
+.Sp
+Fortunately libev seems to be able to work around these idiocies.
+.Sp
+This backend maps \f(CW\*(C`EV_READ\*(C'\fR and \f(CW\*(C`EV_WRITE\*(C'\fR in the same way as
+\&\f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.ie n .IP """EVBACKEND_ALL""" 4
+.el .IP "\f(CWEVBACKEND_ALL\fR" 4
+.IX Item "EVBACKEND_ALL"
+Try all backends (even potentially broken ones that wouldn't be tried
+with \f(CW\*(C`EVFLAG_AUTO\*(C'\fR). Since this is a mask, you can do stuff such as
+\&\f(CW\*(C`EVBACKEND_ALL & ~EVBACKEND_KQUEUE\*(C'\fR.
+.Sp
+It is definitely not recommended to use this flag, use whatever
+\&\f(CW\*(C`ev_recommended_backends ()\*(C'\fR returns, or simply do not specify a backend
+at all.
+.ie n .IP """EVBACKEND_MASK""" 4
+.el .IP "\f(CWEVBACKEND_MASK\fR" 4
+.IX Item "EVBACKEND_MASK"
+Not a backend at all, but a mask to select all backend bits from a
+\&\f(CW\*(C`flags\*(C'\fR value, in case you want to mask out any backends from a flags
+value (e.g. when modifying the \f(CW\*(C`LIBEV_FLAGS\*(C'\fR environment variable).
+.RE
+.RS 4
+.Sp
+If one or more of the backend flags are or'ed into the flags value,
+then only these backends will be tried (in the reverse order as listed
+here). If none are specified, all backends in \f(CW\*(C`ev_recommended_backends
+()\*(C'\fR will be tried.
+.Sp
+Example: Try to create a event loop that uses epoll and nothing else.
+.Sp
+.Vb 3
+\& struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
+\& if (!epoller)
+\& fatal ("no epoll found here, maybe it hides under your chair");
+.Ve
+.Sp
+Example: Use whatever libev has to offer, but make sure that kqueue is
+used if available.
+.Sp
+.Vb 1
+\& struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
+.Ve
+.RE
+.IP "ev_loop_destroy (loop)" 4
+.IX Item "ev_loop_destroy (loop)"
+Destroys an event loop object (frees all memory and kernel state
+etc.). None of the active event watchers will be stopped in the normal
+sense, so e.g. \f(CW\*(C`ev_is_active\*(C'\fR might still return true. It is your
+responsibility to either stop all watchers cleanly yourself \fIbefore\fR
+calling this function, or cope with the fact afterwards (which is usually
+the easiest thing, you can just ignore the watchers and/or \f(CW\*(C`free ()\*(C'\fR them
+for example).
+.Sp
+Note that certain global state, such as signal state (and installed signal
+handlers), will not be freed by this function, and related watchers (such
+as signal and child watchers) would need to be stopped manually.
+.Sp
+This function is normally used on loop objects allocated by
+\&\f(CW\*(C`ev_loop_new\*(C'\fR, but it can also be used on the default loop returned by
+\&\f(CW\*(C`ev_default_loop\*(C'\fR, in which case it is not thread-safe.
+.Sp
+Note that it is not advisable to call this function on the default loop
+except in the rare occasion where you really need to free its resources.
+If you need dynamically allocated loops it is better to use \f(CW\*(C`ev_loop_new\*(C'\fR
+and \f(CW\*(C`ev_loop_destroy\*(C'\fR.
+.IP "ev_loop_fork (loop)" 4
+.IX Item "ev_loop_fork (loop)"
+This function sets a flag that causes subsequent \f(CW\*(C`ev_run\*(C'\fR iterations
+to reinitialise the kernel state for backends that have one. Despite
+the name, you can call it anytime you are allowed to start or stop
+watchers (except inside an \f(CW\*(C`ev_prepare\*(C'\fR callback), but it makes most
+sense after forking, in the child process. You \fImust\fR call it (or use
+\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR) in the child before resuming or calling \f(CW\*(C`ev_run\*(C'\fR.
+.Sp
+In addition, if you want to reuse a loop (via this function or
+\&\f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR), you \fIalso\fR have to ignore \f(CW\*(C`SIGPIPE\*(C'\fR.
+.Sp
+Again, you \fIhave\fR to call it on \fIany\fR loop that you want to re-use after
+a fork, \fIeven if you do not plan to use the loop in the parent\fR. This is
+because some kernel interfaces *cough* \fIkqueue\fR *cough* do funny things
+during fork.
+.Sp
+On the other hand, you only need to call this function in the child
+process if and only if you want to use the event loop in the child. If
+you just fork+exec or create a new loop in the child, you don't have to
+call it at all (in fact, \f(CW\*(C`epoll\*(C'\fR is so badly broken that it makes a
+difference, but libev will usually detect this case on its own and do a
+costly reset of the backend).
+.Sp
+The function itself is quite fast and it's usually not a problem to call
+it just in case after a fork.
+.Sp
+Example: Automate calling \f(CW\*(C`ev_loop_fork\*(C'\fR on the default loop when
+using pthreads.
+.Sp
+.Vb 5
+\& static void
+\& post_fork_child (void)
+\& {
+\& ev_loop_fork (EV_DEFAULT);
+\& }
+\&
+\& ...
+\& pthread_atfork (0, 0, post_fork_child);
+.Ve
+.IP "int ev_is_default_loop (loop)" 4
+.IX Item "int ev_is_default_loop (loop)"
+Returns true when the given loop is, in fact, the default loop, and false
+otherwise.
+.IP "unsigned int ev_iteration (loop)" 4
+.IX Item "unsigned int ev_iteration (loop)"
+Returns the current iteration count for the event loop, which is identical
+to the number of times libev did poll for new events. It starts at \f(CW0\fR
+and happily wraps around with enough iterations.
+.Sp
+This value can sometimes be useful as a generation counter of sorts (it
+\&\*(L"ticks\*(R" the number of loop iterations), as it roughly corresponds with
+\&\f(CW\*(C`ev_prepare\*(C'\fR and \f(CW\*(C`ev_check\*(C'\fR calls \- and is incremented between the
+prepare and check phases.
+.IP "unsigned int ev_depth (loop)" 4
+.IX Item "unsigned int ev_depth (loop)"
+Returns the number of times \f(CW\*(C`ev_run\*(C'\fR was entered minus the number of
+times \f(CW\*(C`ev_run\*(C'\fR was exited normally, in other words, the recursion depth.
+.Sp
+Outside \f(CW\*(C`ev_run\*(C'\fR, this number is zero. In a callback, this number is
+\&\f(CW1\fR, unless \f(CW\*(C`ev_run\*(C'\fR was invoked recursively (or from another thread),
+in which case it is higher.
+.Sp
+Leaving \f(CW\*(C`ev_run\*(C'\fR abnormally (setjmp/longjmp, cancelling the thread,
+throwing an exception etc.), doesn't count as \*(L"exit\*(R" \- consider this
+as a hint to avoid such ungentleman-like behaviour unless it's really
+convenient, in which case it is fully supported.
+.IP "unsigned int ev_backend (loop)" 4
+.IX Item "unsigned int ev_backend (loop)"
+Returns one of the \f(CW\*(C`EVBACKEND_*\*(C'\fR flags indicating the event backend in
+use.
+.IP "ev_tstamp ev_now (loop)" 4
+.IX Item "ev_tstamp ev_now (loop)"
+Returns the current \*(L"event loop time\*(R", which is the time the event loop
+received events and started processing them. This timestamp does not
+change as long as callbacks are being processed, and this is also the base
+time used for relative timers. You can treat it as the timestamp of the
+event occurring (or more correctly, libev finding out about it).
+.IP "ev_now_update (loop)" 4
+.IX Item "ev_now_update (loop)"
+Establishes the current time by querying the kernel, updating the time
+returned by \f(CW\*(C`ev_now ()\*(C'\fR in the progress. This is a costly operation and
+is usually done automatically within \f(CW\*(C`ev_run ()\*(C'\fR.
+.Sp
+This function is rarely useful, but when some event callback runs for a
+very long time without entering the event loop, updating libev's idea of
+the current time is a good idea.
+.Sp
+See also \*(L"The special problem of time updates\*(R" in the \f(CW\*(C`ev_timer\*(C'\fR section.
+.IP "ev_suspend (loop)" 4
+.IX Item "ev_suspend (loop)"
+.PD 0
+.IP "ev_resume (loop)" 4
+.IX Item "ev_resume (loop)"
+.PD
+These two functions suspend and resume an event loop, for use when the
+loop is not used for a while and timeouts should not be processed.
+.Sp
+A typical use case would be an interactive program such as a game: When
+the user presses \f(CW\*(C`^Z\*(C'\fR to suspend the game and resumes it an hour later it
+would be best to handle timeouts as if no time had actually passed while
+the program was suspended. This can be achieved by calling \f(CW\*(C`ev_suspend\*(C'\fR
+in your \f(CW\*(C`SIGTSTP\*(C'\fR handler, sending yourself a \f(CW\*(C`SIGSTOP\*(C'\fR and calling
+\&\f(CW\*(C`ev_resume\*(C'\fR directly afterwards to resume timer processing.
+.Sp
+Effectively, all \f(CW\*(C`ev_timer\*(C'\fR watchers will be delayed by the time spend
+between \f(CW\*(C`ev_suspend\*(C'\fR and \f(CW\*(C`ev_resume\*(C'\fR, and all \f(CW\*(C`ev_periodic\*(C'\fR watchers
+will be rescheduled (that is, they will lose any events that would have
+occurred while suspended).
+.Sp
+After calling \f(CW\*(C`ev_suspend\*(C'\fR you \fBmust not\fR call \fIany\fR function on the
+given loop other than \f(CW\*(C`ev_resume\*(C'\fR, and you \fBmust not\fR call \f(CW\*(C`ev_resume\*(C'\fR
+without a previous call to \f(CW\*(C`ev_suspend\*(C'\fR.
+.Sp
+Calling \f(CW\*(C`ev_suspend\*(C'\fR/\f(CW\*(C`ev_resume\*(C'\fR has the side effect of updating the
+event loop time (see \f(CW\*(C`ev_now_update\*(C'\fR).
+.IP "bool ev_run (loop, int flags)" 4
+.IX Item "bool ev_run (loop, int flags)"
+Finally, this is it, the event handler. This function usually is called
+after you have initialised all your watchers and you want to start
+handling events. It will ask the operating system for any new events, call
+the watcher callbacks, and then repeat the whole process indefinitely: This
+is why event loops are called \fIloops\fR.
+.Sp
+If the flags argument is specified as \f(CW0\fR, it will keep handling events
+until either no event watchers are active anymore or \f(CW\*(C`ev_break\*(C'\fR was
+called.
+.Sp
+The return value is false if there are no more active watchers (which
+usually means \*(L"all jobs done\*(R" or \*(L"deadlock\*(R"), and true in all other cases
+(which usually means " you should call \f(CW\*(C`ev_run\*(C'\fR again").
+.Sp
+Please note that an explicit \f(CW\*(C`ev_break\*(C'\fR is usually better than
+relying on all watchers to be stopped when deciding when a program has
+finished (especially in interactive programs), but having a program
+that automatically loops as long as it has to and no longer by virtue
+of relying on its watchers stopping correctly, that is truly a thing of
+beauty.
+.Sp
+This function is \fImostly\fR exception-safe \- you can break out of a
+\&\f(CW\*(C`ev_run\*(C'\fR call by calling \f(CW\*(C`longjmp\*(C'\fR in a callback, throwing a \*(C+
+exception and so on. This does not decrement the \f(CW\*(C`ev_depth\*(C'\fR value, nor
+will it clear any outstanding \f(CW\*(C`EVBREAK_ONE\*(C'\fR breaks.
+.Sp
+A flags value of \f(CW\*(C`EVRUN_NOWAIT\*(C'\fR will look for new events, will handle
+those events and any already outstanding ones, but will not wait and
+block your process in case there are no events and will return after one
+iteration of the loop. This is sometimes useful to poll and handle new
+events while doing lengthy calculations, to keep the program responsive.
+.Sp
+A flags value of \f(CW\*(C`EVRUN_ONCE\*(C'\fR will look for new events (waiting if
+necessary) and will handle those and any already outstanding ones. It
+will block your process until at least one new event arrives (which could
+be an event internal to libev itself, so there is no guarantee that a
+user-registered callback will be called), and will return after one
+iteration of the loop.
+.Sp
+This is useful if you are waiting for some external event in conjunction
+with something not expressible using other libev watchers (i.e. "roll your
+own \f(CW\*(C`ev_run\*(C'\fR"). However, a pair of \f(CW\*(C`ev_prepare\*(C'\fR/\f(CW\*(C`ev_check\*(C'\fR watchers is
+usually a better approach for this kind of thing.
+.Sp
+Here are the gory details of what \f(CW\*(C`ev_run\*(C'\fR does (this is for your
+understanding, not a guarantee that things will work exactly like this in
+future versions):
+.Sp
+.Vb 10
+\& \- Increment loop depth.
+\& \- Reset the ev_break status.
+\& \- Before the first iteration, call any pending watchers.
+\& LOOP:
+\& \- If EVFLAG_FORKCHECK was used, check for a fork.
+\& \- If a fork was detected (by any means), queue and call all fork watchers.
+\& \- Queue and call all prepare watchers.
+\& \- If ev_break was called, goto FINISH.
+\& \- If we have been forked, detach and recreate the kernel state
+\& as to not disturb the other process.
+\& \- Update the kernel state with all outstanding changes.
+\& \- Update the "event loop time" (ev_now ()).
+\& \- Calculate for how long to sleep or block, if at all
+\& (active idle watchers, EVRUN_NOWAIT or not having
+\& any active watchers at all will result in not sleeping).
+\& \- Sleep if the I/O and timer collect interval say so.
+\& \- Increment loop iteration counter.
+\& \- Block the process, waiting for any events.
+\& \- Queue all outstanding I/O (fd) events.
+\& \- Update the "event loop time" (ev_now ()), and do time jump adjustments.
+\& \- Queue all expired timers.
+\& \- Queue all expired periodics.
+\& \- Queue all idle watchers with priority higher than that of pending events.
+\& \- Queue all check watchers.
+\& \- Call all queued watchers in reverse order (i.e. check watchers first).
+\& Signals and child watchers are implemented as I/O watchers, and will
+\& be handled here by queueing them when their watcher gets executed.
+\& \- If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
+\& were used, or there are no active watchers, goto FINISH, otherwise
+\& continue with step LOOP.
+\& FINISH:
+\& \- Reset the ev_break status iff it was EVBREAK_ONE.
+\& \- Decrement the loop depth.
+\& \- Return.
+.Ve
+.Sp
+Example: Queue some jobs and then loop until no events are outstanding
+anymore.
+.Sp
+.Vb 4
+\& ... queue jobs here, make sure they register event watchers as long
+\& ... as they still have work to do (even an idle watcher will do..)
+\& ev_run (my_loop, 0);
+\& ... jobs done or somebody called break. yeah!
+.Ve
+.IP "ev_break (loop, how)" 4
+.IX Item "ev_break (loop, how)"
+Can be used to make a call to \f(CW\*(C`ev_run\*(C'\fR return early (but only after it
+has processed all outstanding events). The \f(CW\*(C`how\*(C'\fR argument must be either
+\&\f(CW\*(C`EVBREAK_ONE\*(C'\fR, which will make the innermost \f(CW\*(C`ev_run\*(C'\fR call return, or
+\&\f(CW\*(C`EVBREAK_ALL\*(C'\fR, which will make all nested \f(CW\*(C`ev_run\*(C'\fR calls return.
+.Sp
+This \*(L"break state\*(R" will be cleared on the next call to \f(CW\*(C`ev_run\*(C'\fR.
+.Sp
+It is safe to call \f(CW\*(C`ev_break\*(C'\fR from outside any \f(CW\*(C`ev_run\*(C'\fR calls, too, in
+which case it will have no effect.
+.IP "ev_ref (loop)" 4
+.IX Item "ev_ref (loop)"
+.PD 0
+.IP "ev_unref (loop)" 4
+.IX Item "ev_unref (loop)"
+.PD
+Ref/unref can be used to add or remove a reference count on the event
+loop: Every watcher keeps one reference, and as long as the reference
+count is nonzero, \f(CW\*(C`ev_run\*(C'\fR will not return on its own.
+.Sp
+This is useful when you have a watcher that you never intend to
+unregister, but that nevertheless should not keep \f(CW\*(C`ev_run\*(C'\fR from
+returning. In such a case, call \f(CW\*(C`ev_unref\*(C'\fR after starting, and \f(CW\*(C`ev_ref\*(C'\fR
+before stopping it.
+.Sp
+As an example, libev itself uses this for its internal signal pipe: It
+is not visible to the libev user and should not keep \f(CW\*(C`ev_run\*(C'\fR from
+exiting if no event watchers registered by it are active. It is also an
+excellent way to do this for generic recurring timers or from within
+third-party libraries. Just remember to \fIunref after start\fR and \fIref
+before stop\fR (but only if the watcher wasn't active before, or was active
+before, respectively. Note also that libev might stop watchers itself
+(e.g. non-repeating timers) in which case you have to \f(CW\*(C`ev_ref\*(C'\fR
+in the callback).
+.Sp
+Example: Create a signal watcher, but keep it from keeping \f(CW\*(C`ev_run\*(C'\fR
+running when nothing else is active.
+.Sp
+.Vb 4
+\& ev_signal exitsig;
+\& ev_signal_init (&exitsig, sig_cb, SIGINT);
+\& ev_signal_start (loop, &exitsig);
+\& ev_unref (loop);
+.Ve
+.Sp
+Example: For some weird reason, unregister the above signal handler again.
+.Sp
+.Vb 2
+\& ev_ref (loop);
+\& ev_signal_stop (loop, &exitsig);
+.Ve
+.IP "ev_set_io_collect_interval (loop, ev_tstamp interval)" 4
+.IX Item "ev_set_io_collect_interval (loop, ev_tstamp interval)"
+.PD 0
+.IP "ev_set_timeout_collect_interval (loop, ev_tstamp interval)" 4
+.IX Item "ev_set_timeout_collect_interval (loop, ev_tstamp interval)"
+.PD
+These advanced functions influence the time that libev will spend waiting
+for events. Both time intervals are by default \f(CW0\fR, meaning that libev
+will try to invoke timer/periodic callbacks and I/O callbacks with minimum
+latency.
+.Sp
+Setting these to a higher value (the \f(CW\*(C`interval\*(C'\fR \fImust\fR be >= \f(CW0\fR)
+allows libev to delay invocation of I/O and timer/periodic callbacks
+to increase efficiency of loop iterations (or to increase power-saving
+opportunities).
+.Sp
+The idea is that sometimes your program runs just fast enough to handle
+one (or very few) event(s) per loop iteration. While this makes the
+program responsive, it also wastes a lot of \s-1CPU\s0 time to poll for new
+events, especially with backends like \f(CW\*(C`select ()\*(C'\fR which have a high
+overhead for the actual polling but can deliver many events at once.
+.Sp
+By setting a higher \fIio collect interval\fR you allow libev to spend more
+time collecting I/O events, so you can handle more events per iteration,
+at the cost of increasing latency. Timeouts (both \f(CW\*(C`ev_periodic\*(C'\fR and
+\&\f(CW\*(C`ev_timer\*(C'\fR) will not be affected. Setting this to a non-null value will
+introduce an additional \f(CW\*(C`ev_sleep ()\*(C'\fR call into most loop iterations. The
+sleep time ensures that libev will not poll for I/O events more often then
+once per this interval, on average (as long as the host time resolution is
+good enough).
+.Sp
+Likewise, by setting a higher \fItimeout collect interval\fR you allow libev
+to spend more time collecting timeouts, at the expense of increased
+latency/jitter/inexactness (the watcher callback will be called
+later). \f(CW\*(C`ev_io\*(C'\fR watchers will not be affected. Setting this to a non-null
+value will not introduce any overhead in libev.
+.Sp
+Many (busy) programs can usually benefit by setting the I/O collect
+interval to a value near \f(CW0.1\fR or so, which is often enough for
+interactive servers (of course not for games), likewise for timeouts. It
+usually doesn't make much sense to set it to a lower value than \f(CW0.01\fR,
+as this approaches the timing granularity of most systems. Note that if
+you do transactions with the outside world and you can't increase the
+parallelity, then this setting will limit your transaction rate (if you
+need to poll once per transaction and the I/O collect interval is 0.01,
+then you can't do more than 100 transactions per second).
+.Sp
+Setting the \fItimeout collect interval\fR can improve the opportunity for
+saving power, as the program will \*(L"bundle\*(R" timer callback invocations that
+are \*(L"near\*(R" in time together, by delaying some, thus reducing the number of
+times the process sleeps and wakes up again. Another useful technique to
+reduce iterations/wake\-ups is to use \f(CW\*(C`ev_periodic\*(C'\fR watchers and make sure
+they fire on, say, one-second boundaries only.
+.Sp
+Example: we only need 0.1s timeout granularity, and we wish not to poll
+more often than 100 times per second:
+.Sp
+.Vb 2
+\& ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1);
+\& ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
+.Ve
+.IP "ev_invoke_pending (loop)" 4
+.IX Item "ev_invoke_pending (loop)"
+This call will simply invoke all pending watchers while resetting their
+pending state. Normally, \f(CW\*(C`ev_run\*(C'\fR does this automatically when required,
+but when overriding the invoke callback this call comes handy. This
+function can be invoked from a watcher \- this can be useful for example
+when you want to do some lengthy calculation and want to pass further
+event handling to another thread (you still have to make sure only one
+thread executes within \f(CW\*(C`ev_invoke_pending\*(C'\fR or \f(CW\*(C`ev_run\*(C'\fR of course).
+.IP "int ev_pending_count (loop)" 4
+.IX Item "int ev_pending_count (loop)"
+Returns the number of pending watchers \- zero indicates that no watchers
+are pending.
+.IP "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(\s-1EV_P\s0))" 4
+.IX Item "ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))"
+This overrides the invoke pending functionality of the loop: Instead of
+invoking all pending watchers when there are any, \f(CW\*(C`ev_run\*(C'\fR will call
+this callback instead. This is useful, for example, when you want to
+invoke the actual watchers inside another context (another thread etc.).
+.Sp
+If you want to reset the callback, use \f(CW\*(C`ev_invoke_pending\*(C'\fR as new
+callback.
+.IP "ev_set_loop_release_cb (loop, void (*release)(\s-1EV_P\s0) throw (), void (*acquire)(\s-1EV_P\s0) throw ())" 4
+.IX Item "ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ())"
+Sometimes you want to share the same loop between multiple threads. This
+can be done relatively simply by putting mutex_lock/unlock calls around
+each call to a libev function.
+.Sp
+However, \f(CW\*(C`ev_run\*(C'\fR can run an indefinite time, so it is not feasible
+to wait for it to return. One way around this is to wake up the event
+loop via \f(CW\*(C`ev_break\*(C'\fR and \f(CW\*(C`ev_async_send\*(C'\fR, another way is to set these
+\&\fIrelease\fR and \fIacquire\fR callbacks on the loop.
+.Sp
+When set, then \f(CW\*(C`release\*(C'\fR will be called just before the thread is
+suspended waiting for new events, and \f(CW\*(C`acquire\*(C'\fR is called just
+afterwards.
+.Sp
+Ideally, \f(CW\*(C`release\*(C'\fR will just call your mutex_unlock function, and
+\&\f(CW\*(C`acquire\*(C'\fR will just call the mutex_lock function again.
+.Sp
+While event loop modifications are allowed between invocations of
+\&\f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR (that's their only purpose after all), no
+modifications done will affect the event loop, i.e. adding watchers will
+have no effect on the set of file descriptors being watched, or the time
+waited. Use an \f(CW\*(C`ev_async\*(C'\fR watcher to wake up \f(CW\*(C`ev_run\*(C'\fR when you want it
+to take note of any changes you made.
+.Sp
+In theory, threads executing \f(CW\*(C`ev_run\*(C'\fR will be async-cancel safe between
+invocations of \f(CW\*(C`release\*(C'\fR and \f(CW\*(C`acquire\*(C'\fR.
+.Sp
+See also the locking example in the \f(CW\*(C`THREADS\*(C'\fR section later in this
+document.
+.IP "ev_set_userdata (loop, void *data)" 4
+.IX Item "ev_set_userdata (loop, void *data)"
+.PD 0
+.IP "void *ev_userdata (loop)" 4
+.IX Item "void *ev_userdata (loop)"
+.PD
+Set and retrieve a single \f(CW\*(C`void *\*(C'\fR associated with a loop. When
+\&\f(CW\*(C`ev_set_userdata\*(C'\fR has never been called, then \f(CW\*(C`ev_userdata\*(C'\fR returns
+\&\f(CW0\fR.
+.Sp
+These two functions can be used to associate arbitrary data with a loop,
+and are intended solely for the \f(CW\*(C`invoke_pending_cb\*(C'\fR, \f(CW\*(C`release\*(C'\fR and
+\&\f(CW\*(C`acquire\*(C'\fR callbacks described above, but of course can be (ab\-)used for
+any other purpose as well.
+.IP "ev_verify (loop)" 4
+.IX Item "ev_verify (loop)"
+This function only does something when \f(CW\*(C`EV_VERIFY\*(C'\fR support has been
+compiled in, which is the default for non-minimal builds. It tries to go
+through all internal structures and checks them for validity. If anything
+is found to be inconsistent, it will print an error message to standard
+error and call \f(CW\*(C`abort ()\*(C'\fR.
+.Sp
+This can be used to catch bugs inside libev itself: under normal
+circumstances, this function will never abort as of course libev keeps its
+data structures consistent.
+.SH "ANATOMY OF A WATCHER"
+.IX Header "ANATOMY OF A WATCHER"
+In the following description, uppercase \f(CW\*(C`TYPE\*(C'\fR in names stands for the
+watcher type, e.g. \f(CW\*(C`ev_TYPE_start\*(C'\fR can mean \f(CW\*(C`ev_timer_start\*(C'\fR for timer
+watchers and \f(CW\*(C`ev_io_start\*(C'\fR for I/O watchers.
+.PP
+A watcher is an opaque structure that you allocate and register to record
+your interest in some event. To make a concrete example, imagine you want
+to wait for \s-1STDIN\s0 to become readable, you would create an \f(CW\*(C`ev_io\*(C'\fR watcher
+for that:
+.PP
+.Vb 5
+\& static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
+\& {
+\& ev_io_stop (w);
+\& ev_break (loop, EVBREAK_ALL);
+\& }
+\&
+\& struct ev_loop *loop = ev_default_loop (0);
+\&
+\& ev_io stdin_watcher;
+\&
+\& ev_init (&stdin_watcher, my_cb);
+\& ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
+\& ev_io_start (loop, &stdin_watcher);
+\&
+\& ev_run (loop, 0);
+.Ve
+.PP
+As you can see, you are responsible for allocating the memory for your
+watcher structures (and it is \fIusually\fR a bad idea to do this on the
+stack).
+.PP
+Each watcher has an associated watcher structure (called \f(CW\*(C`struct ev_TYPE\*(C'\fR
+or simply \f(CW\*(C`ev_TYPE\*(C'\fR, as typedefs are provided for all watcher structs).
+.PP
+Each watcher structure must be initialised by a call to \f(CW\*(C`ev_init (watcher
+*, callback)\*(C'\fR, which expects a callback to be provided. This callback is
+invoked each time the event occurs (or, in the case of I/O watchers, each
+time the event loop detects that the file descriptor given is readable
+and/or writable).
+.PP
+Each watcher type further has its own \f(CW\*(C`ev_TYPE_set (watcher *, ...)\*(C'\fR
+macro to configure it, with arguments specific to the watcher type. There
+is also a macro to combine initialisation and setting in one call: \f(CW\*(C`ev_TYPE_init (watcher *, callback, ...)\*(C'\fR.
+.PP
+To make the watcher actually watch out for events, you have to start it
+with a watcher-specific start function (\f(CW\*(C`ev_TYPE_start (loop, watcher
+*)\*(C'\fR), and you can stop watching for events at any time by calling the
+corresponding stop function (\f(CW\*(C`ev_TYPE_stop (loop, watcher *)\*(C'\fR.
+.PP
+As long as your watcher is active (has been started but not stopped) you
+must not touch the values stored in it. Most specifically you must never
+reinitialise it or call its \f(CW\*(C`ev_TYPE_set\*(C'\fR macro.
+.PP
+Each and every callback receives the event loop pointer as first, the
+registered watcher structure as second, and a bitset of received events as
+third argument.
+.PP
+The received events usually include a single bit per event type received
+(you can receive multiple events at the same time). The possible bit masks
+are:
+.ie n .IP """EV_READ""" 4
+.el .IP "\f(CWEV_READ\fR" 4
+.IX Item "EV_READ"
+.PD 0
+.ie n .IP """EV_WRITE""" 4
+.el .IP "\f(CWEV_WRITE\fR" 4
+.IX Item "EV_WRITE"
+.PD
+The file descriptor in the \f(CW\*(C`ev_io\*(C'\fR watcher has become readable and/or
+writable.
+.ie n .IP """EV_TIMER""" 4
+.el .IP "\f(CWEV_TIMER\fR" 4
+.IX Item "EV_TIMER"
+The \f(CW\*(C`ev_timer\*(C'\fR watcher has timed out.
+.ie n .IP """EV_PERIODIC""" 4
+.el .IP "\f(CWEV_PERIODIC\fR" 4
+.IX Item "EV_PERIODIC"
+The \f(CW\*(C`ev_periodic\*(C'\fR watcher has timed out.
+.ie n .IP """EV_SIGNAL""" 4
+.el .IP "\f(CWEV_SIGNAL\fR" 4
+.IX Item "EV_SIGNAL"
+The signal specified in the \f(CW\*(C`ev_signal\*(C'\fR watcher has been received by a thread.
+.ie n .IP """EV_CHILD""" 4
+.el .IP "\f(CWEV_CHILD\fR" 4
+.IX Item "EV_CHILD"
+The pid specified in the \f(CW\*(C`ev_child\*(C'\fR watcher has received a status change.
+.ie n .IP """EV_STAT""" 4
+.el .IP "\f(CWEV_STAT\fR" 4
+.IX Item "EV_STAT"
+The path specified in the \f(CW\*(C`ev_stat\*(C'\fR watcher changed its attributes somehow.
+.ie n .IP """EV_IDLE""" 4
+.el .IP "\f(CWEV_IDLE\fR" 4
+.IX Item "EV_IDLE"
+The \f(CW\*(C`ev_idle\*(C'\fR watcher has determined that you have nothing better to do.
+.ie n .IP """EV_PREPARE""" 4
+.el .IP "\f(CWEV_PREPARE\fR" 4
+.IX Item "EV_PREPARE"
+.PD 0
+.ie n .IP """EV_CHECK""" 4
+.el .IP "\f(CWEV_CHECK\fR" 4
+.IX Item "EV_CHECK"
+.PD
+All \f(CW\*(C`ev_prepare\*(C'\fR watchers are invoked just \fIbefore\fR \f(CW\*(C`ev_run\*(C'\fR starts to
+gather new events, and all \f(CW\*(C`ev_check\*(C'\fR watchers are queued (not invoked)
+just after \f(CW\*(C`ev_run\*(C'\fR has gathered them, but before it queues any callbacks
+for any received events. That means \f(CW\*(C`ev_prepare\*(C'\fR watchers are the last
+watchers invoked before the event loop sleeps or polls for new events, and
+\&\f(CW\*(C`ev_check\*(C'\fR watchers will be invoked before any other watchers of the same
+or lower priority within an event loop iteration.
+.Sp
+Callbacks of both watcher types can start and stop as many watchers as
+they want, and all of them will be taken into account (for example, a
+\&\f(CW\*(C`ev_prepare\*(C'\fR watcher might start an idle watcher to keep \f(CW\*(C`ev_run\*(C'\fR from
+blocking).
+.ie n .IP """EV_EMBED""" 4
+.el .IP "\f(CWEV_EMBED\fR" 4
+.IX Item "EV_EMBED"
+The embedded event loop specified in the \f(CW\*(C`ev_embed\*(C'\fR watcher needs attention.
+.ie n .IP """EV_FORK""" 4
+.el .IP "\f(CWEV_FORK\fR" 4
+.IX Item "EV_FORK"
+The event loop has been resumed in the child process after fork (see
+\&\f(CW\*(C`ev_fork\*(C'\fR).
+.ie n .IP """EV_CLEANUP""" 4
+.el .IP "\f(CWEV_CLEANUP\fR" 4
+.IX Item "EV_CLEANUP"
+The event loop is about to be destroyed (see \f(CW\*(C`ev_cleanup\*(C'\fR).
+.ie n .IP """EV_ASYNC""" 4
+.el .IP "\f(CWEV_ASYNC\fR" 4
+.IX Item "EV_ASYNC"
+The given async watcher has been asynchronously notified (see \f(CW\*(C`ev_async\*(C'\fR).
+.ie n .IP """EV_CUSTOM""" 4
+.el .IP "\f(CWEV_CUSTOM\fR" 4
+.IX Item "EV_CUSTOM"
+Not ever sent (or otherwise used) by libev itself, but can be freely used
+by libev users to signal watchers (e.g. via \f(CW\*(C`ev_feed_event\*(C'\fR).
+.ie n .IP """EV_ERROR""" 4
+.el .IP "\f(CWEV_ERROR\fR" 4
+.IX Item "EV_ERROR"
+An unspecified error has occurred, the watcher has been stopped. This might
+happen because the watcher could not be properly started because libev
+ran out of memory, a file descriptor was found to be closed or any other
+problem. Libev considers these application bugs.
+.Sp
+You best act on it by reporting the problem and somehow coping with the
+watcher being stopped. Note that well-written programs should not receive
+an error ever, so when your watcher receives it, this usually indicates a
+bug in your program.
+.Sp
+Libev will usually signal a few \*(L"dummy\*(R" events together with an error, for
+example it might indicate that a fd is readable or writable, and if your
+callbacks is well-written it can just attempt the operation and cope with
+the error from \fIread()\fR or \fIwrite()\fR. This will not work in multi-threaded
+programs, though, as the fd could already be closed and reused for another
+thing, so beware.
+.SS "\s-1GENERIC WATCHER FUNCTIONS\s0"
+.IX Subsection "GENERIC WATCHER FUNCTIONS"
+.ie n .IP """ev_init"" (ev_TYPE *watcher, callback)" 4
+.el .IP "\f(CWev_init\fR (ev_TYPE *watcher, callback)" 4
+.IX Item "ev_init (ev_TYPE *watcher, callback)"
+This macro initialises the generic portion of a watcher. The contents
+of the watcher object can be arbitrary (so \f(CW\*(C`malloc\*(C'\fR will do). Only
+the generic parts of the watcher are initialised, you \fIneed\fR to call
+the type-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR macro afterwards to initialise the
+type-specific parts. For each type there is also a \f(CW\*(C`ev_TYPE_init\*(C'\fR macro
+which rolls both calls into one.
+.Sp
+You can reinitialise a watcher at any time as long as it has been stopped
+(or never started) and there are no pending events outstanding.
+.Sp
+The callback is always of type \f(CW\*(C`void (*)(struct ev_loop *loop, ev_TYPE *watcher,
+int revents)\*(C'\fR.
+.Sp
+Example: Initialise an \f(CW\*(C`ev_io\*(C'\fR watcher in two steps.
+.Sp
+.Vb 3
+\& ev_io w;
+\& ev_init (&w, my_cb);
+\& ev_io_set (&w, STDIN_FILENO, EV_READ);
+.Ve
+.ie n .IP """ev_TYPE_set"" (ev_TYPE *watcher, [args])" 4
+.el .IP "\f(CWev_TYPE_set\fR (ev_TYPE *watcher, [args])" 4
+.IX Item "ev_TYPE_set (ev_TYPE *watcher, [args])"
+This macro initialises the type-specific parts of a watcher. You need to
+call \f(CW\*(C`ev_init\*(C'\fR at least once before you call this macro, but you can
+call \f(CW\*(C`ev_TYPE_set\*(C'\fR any number of times. You must not, however, call this
+macro on a watcher that is active (it can be pending, however, which is a
+difference to the \f(CW\*(C`ev_init\*(C'\fR macro).
+.Sp
+Although some watcher types do not have type-specific arguments
+(e.g. \f(CW\*(C`ev_prepare\*(C'\fR) you still need to call its \f(CW\*(C`set\*(C'\fR macro.
+.Sp
+See \f(CW\*(C`ev_init\*(C'\fR, above, for an example.
+.ie n .IP """ev_TYPE_init"" (ev_TYPE *watcher, callback, [args])" 4
+.el .IP "\f(CWev_TYPE_init\fR (ev_TYPE *watcher, callback, [args])" 4
+.IX Item "ev_TYPE_init (ev_TYPE *watcher, callback, [args])"
+This convenience macro rolls both \f(CW\*(C`ev_init\*(C'\fR and \f(CW\*(C`ev_TYPE_set\*(C'\fR macro
+calls into a single call. This is the most convenient method to initialise
+a watcher. The same limitations apply, of course.
+.Sp
+Example: Initialise and set an \f(CW\*(C`ev_io\*(C'\fR watcher in one step.
+.Sp
+.Vb 1
+\& ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
+.Ve
+.ie n .IP """ev_TYPE_start"" (loop, ev_TYPE *watcher)" 4
+.el .IP "\f(CWev_TYPE_start\fR (loop, ev_TYPE *watcher)" 4
+.IX Item "ev_TYPE_start (loop, ev_TYPE *watcher)"
+Starts (activates) the given watcher. Only active watchers will receive
+events. If the watcher is already active nothing will happen.
+.Sp
+Example: Start the \f(CW\*(C`ev_io\*(C'\fR watcher that is being abused as example in this
+whole section.
+.Sp
+.Vb 1
+\& ev_io_start (EV_DEFAULT_UC, &w);
+.Ve
+.ie n .IP """ev_TYPE_stop"" (loop, ev_TYPE *watcher)" 4
+.el .IP "\f(CWev_TYPE_stop\fR (loop, ev_TYPE *watcher)" 4
+.IX Item "ev_TYPE_stop (loop, ev_TYPE *watcher)"
+Stops the given watcher if active, and clears the pending status (whether
+the watcher was active or not).
+.Sp
+It is possible that stopped watchers are pending \- for example,
+non-repeating timers are being stopped when they become pending \- but
+calling \f(CW\*(C`ev_TYPE_stop\*(C'\fR ensures that the watcher is neither active nor
+pending. If you want to free or reuse the memory used by the watcher it is
+therefore a good idea to always call its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function.
+.IP "bool ev_is_active (ev_TYPE *watcher)" 4
+.IX Item "bool ev_is_active (ev_TYPE *watcher)"
+Returns a true value iff the watcher is active (i.e. it has been started
+and not yet been stopped). As long as a watcher is active you must not modify
+it.
+.IP "bool ev_is_pending (ev_TYPE *watcher)" 4
+.IX Item "bool ev_is_pending (ev_TYPE *watcher)"
+Returns a true value iff the watcher is pending, (i.e. it has outstanding
+events but its callback has not yet been invoked). As long as a watcher
+is pending (but not active) you must not call an init function on it (but
+\&\f(CW\*(C`ev_TYPE_set\*(C'\fR is safe), you must not change its priority, and you must
+make sure the watcher is available to libev (e.g. you cannot \f(CW\*(C`free ()\*(C'\fR
+it).
+.IP "callback ev_cb (ev_TYPE *watcher)" 4
+.IX Item "callback ev_cb (ev_TYPE *watcher)"
+Returns the callback currently set on the watcher.
+.IP "ev_set_cb (ev_TYPE *watcher, callback)" 4
+.IX Item "ev_set_cb (ev_TYPE *watcher, callback)"
+Change the callback. You can change the callback at virtually any time
+(modulo threads).
+.IP "ev_set_priority (ev_TYPE *watcher, int priority)" 4
+.IX Item "ev_set_priority (ev_TYPE *watcher, int priority)"
+.PD 0
+.IP "int ev_priority (ev_TYPE *watcher)" 4
+.IX Item "int ev_priority (ev_TYPE *watcher)"
+.PD
+Set and query the priority of the watcher. The priority is a small
+integer between \f(CW\*(C`EV_MAXPRI\*(C'\fR (default: \f(CW2\fR) and \f(CW\*(C`EV_MINPRI\*(C'\fR
+(default: \f(CW\*(C`\-2\*(C'\fR). Pending watchers with higher priority will be invoked
+before watchers with lower priority, but priority will not keep watchers
+from being executed (except for \f(CW\*(C`ev_idle\*(C'\fR watchers).
+.Sp
+If you need to suppress invocation when higher priority events are pending
+you need to look at \f(CW\*(C`ev_idle\*(C'\fR watchers, which provide this functionality.
+.Sp
+You \fImust not\fR change the priority of a watcher as long as it is active or
+pending.
+.Sp
+Setting a priority outside the range of \f(CW\*(C`EV_MINPRI\*(C'\fR to \f(CW\*(C`EV_MAXPRI\*(C'\fR is
+fine, as long as you do not mind that the priority value you query might
+or might not have been clamped to the valid range.
+.Sp
+The default priority used by watchers when no priority has been set is
+always \f(CW0\fR, which is supposed to not be too high and not be too low :).
+.Sp
+See \*(L"\s-1WATCHER PRIORITY MODELS\*(R"\s0, below, for a more thorough treatment of
+priorities.
+.IP "ev_invoke (loop, ev_TYPE *watcher, int revents)" 4
+.IX Item "ev_invoke (loop, ev_TYPE *watcher, int revents)"
+Invoke the \f(CW\*(C`watcher\*(C'\fR with the given \f(CW\*(C`loop\*(C'\fR and \f(CW\*(C`revents\*(C'\fR. Neither
+\&\f(CW\*(C`loop\*(C'\fR nor \f(CW\*(C`revents\*(C'\fR need to be valid as long as the watcher callback
+can deal with that fact, as both are simply passed through to the
+callback.
+.IP "int ev_clear_pending (loop, ev_TYPE *watcher)" 4
+.IX Item "int ev_clear_pending (loop, ev_TYPE *watcher)"
+If the watcher is pending, this function clears its pending status and
+returns its \f(CW\*(C`revents\*(C'\fR bitset (as if its callback was invoked). If the
+watcher isn't pending it does nothing and returns \f(CW0\fR.
+.Sp
+Sometimes it can be useful to \*(L"poll\*(R" a watcher instead of waiting for its
+callback to be invoked, which can be accomplished with this function.
+.IP "ev_feed_event (loop, ev_TYPE *watcher, int revents)" 4
+.IX Item "ev_feed_event (loop, ev_TYPE *watcher, int revents)"
+Feeds the given event set into the event loop, as if the specified event
+had happened for the specified watcher (which must be a pointer to an
+initialised but not necessarily started event watcher). Obviously you must
+not free the watcher as long as it has pending events.
+.Sp
+Stopping the watcher, letting libev invoke it, or calling
+\&\f(CW\*(C`ev_clear_pending\*(C'\fR will clear the pending event, even if the watcher was
+not started in the first place.
+.Sp
+See also \f(CW\*(C`ev_feed_fd_event\*(C'\fR and \f(CW\*(C`ev_feed_signal_event\*(C'\fR for related
+functions that do not need a watcher.
+.PP
+See also the \*(L"\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\*(R"\s0 and \*(L"\s-1BUILDING YOUR
+OWN COMPOSITE WATCHERS\*(R"\s0 idioms.
+.SS "\s-1WATCHER STATES\s0"
+.IX Subsection "WATCHER STATES"
+There are various watcher states mentioned throughout this manual \-
+active, pending and so on. In this section these states and the rules to
+transition between them will be described in more detail \- and while these
+rules might look complicated, they usually do \*(L"the right thing\*(R".
+.IP "initialised" 4
+.IX Item "initialised"
+Before a watcher can be registered with the event loop it has to be
+initialised. This can be done with a call to \f(CW\*(C`ev_TYPE_init\*(C'\fR, or calls to
+\&\f(CW\*(C`ev_init\*(C'\fR followed by the watcher-specific \f(CW\*(C`ev_TYPE_set\*(C'\fR function.
+.Sp
+In this state it is simply some block of memory that is suitable for
+use in an event loop. It can be moved around, freed, reused etc. at
+will \- as long as you either keep the memory contents intact, or call
+\&\f(CW\*(C`ev_TYPE_init\*(C'\fR again.
+.IP "started/running/active" 4
+.IX Item "started/running/active"
+Once a watcher has been started with a call to \f(CW\*(C`ev_TYPE_start\*(C'\fR it becomes
+property of the event loop, and is actively waiting for events. While in
+this state it cannot be accessed (except in a few documented ways), moved,
+freed or anything else \- the only legal thing is to keep a pointer to it,
+and call libev functions on it that are documented to work on active watchers.
+.IP "pending" 4
+.IX Item "pending"
+If a watcher is active and libev determines that an event it is interested
+in has occurred (such as a timer expiring), it will become pending. It will
+stay in this pending state until either it is stopped or its callback is
+about to be invoked, so it is not normally pending inside the watcher
+callback.
+.Sp
+The watcher might or might not be active while it is pending (for example,
+an expired non-repeating timer can be pending but no longer active). If it
+is stopped, it can be freely accessed (e.g. by calling \f(CW\*(C`ev_TYPE_set\*(C'\fR),
+but it is still property of the event loop at this time, so cannot be
+moved, freed or reused. And if it is active the rules described in the
+previous item still apply.
+.Sp
+It is also possible to feed an event on a watcher that is not active (e.g.
+via \f(CW\*(C`ev_feed_event\*(C'\fR), in which case it becomes pending without being
+active.
+.IP "stopped" 4
+.IX Item "stopped"
+A watcher can be stopped implicitly by libev (in which case it might still
+be pending), or explicitly by calling its \f(CW\*(C`ev_TYPE_stop\*(C'\fR function. The
+latter will clear any pending state the watcher might be in, regardless
+of whether it was active or not, so stopping a watcher explicitly before
+freeing it is often a good idea.
+.Sp
+While stopped (and not pending) the watcher is essentially in the
+initialised state, that is, it can be reused, moved, modified in any way
+you wish (but when you trash the memory block, you need to \f(CW\*(C`ev_TYPE_init\*(C'\fR
+it again).
+.SS "\s-1WATCHER PRIORITY MODELS\s0"
+.IX Subsection "WATCHER PRIORITY MODELS"
+Many event loops support \fIwatcher priorities\fR, which are usually small
+integers that influence the ordering of event callback invocation
+between watchers in some way, all else being equal.
+.PP
+In libev, Watcher priorities can be set using \f(CW\*(C`ev_set_priority\*(C'\fR. See its
+description for the more technical details such as the actual priority
+range.
+.PP
+There are two common ways how these these priorities are being interpreted
+by event loops:
+.PP
+In the more common lock-out model, higher priorities \*(L"lock out\*(R" invocation
+of lower priority watchers, which means as long as higher priority
+watchers receive events, lower priority watchers are not being invoked.
+.PP
+The less common only-for-ordering model uses priorities solely to order
+callback invocation within a single event loop iteration: Higher priority
+watchers are invoked before lower priority ones, but they all get invoked
+before polling for new events.
+.PP
+Libev uses the second (only-for-ordering) model for all its watchers
+except for idle watchers (which use the lock-out model).
+.PP
+The rationale behind this is that implementing the lock-out model for
+watchers is not well supported by most kernel interfaces, and most event
+libraries will just poll for the same events again and again as long as
+their callbacks have not been executed, which is very inefficient in the
+common case of one high-priority watcher locking out a mass of lower
+priority ones.
+.PP
+Static (ordering) priorities are most useful when you have two or more
+watchers handling the same resource: a typical usage example is having an
+\&\f(CW\*(C`ev_io\*(C'\fR watcher to receive data, and an associated \f(CW\*(C`ev_timer\*(C'\fR to handle
+timeouts. Under load, data might be received while the program handles
+other jobs, but since timers normally get invoked first, the timeout
+handler will be executed before checking for data. In that case, giving
+the timer a lower priority than the I/O watcher ensures that I/O will be
+handled first even under adverse conditions (which is usually, but not
+always, what you want).
+.PP
+Since idle watchers use the \*(L"lock-out\*(R" model, meaning that idle watchers
+will only be executed when no same or higher priority watchers have
+received events, they can be used to implement the \*(L"lock-out\*(R" model when
+required.
+.PP
+For example, to emulate how many other event libraries handle priorities,
+you can associate an \f(CW\*(C`ev_idle\*(C'\fR watcher to each such watcher, and in
+the normal watcher callback, you just start the idle watcher. The real
+processing is done in the idle watcher callback. This causes libev to
+continuously poll and process kernel event data for the watcher, but when
+the lock-out case is known to be rare (which in turn is rare :), this is
+workable.
+.PP
+Usually, however, the lock-out model implemented that way will perform
+miserably under the type of load it was designed to handle. In that case,
+it might be preferable to stop the real watcher before starting the
+idle watcher, so the kernel will not have to process the event in case
+the actual processing will be delayed for considerable time.
+.PP
+Here is an example of an I/O watcher that should run at a strictly lower
+priority than the default, and which should only process data when no
+other events are pending:
+.PP
+.Vb 2
+\& ev_idle idle; // actual processing watcher
+\& ev_io io; // actual event watcher
+\&
+\& static void
+\& io_cb (EV_P_ ev_io *w, int revents)
+\& {
+\& // stop the I/O watcher, we received the event, but
+\& // are not yet ready to handle it.
+\& ev_io_stop (EV_A_ w);
+\&
+\& // start the idle watcher to handle the actual event.
+\& // it will not be executed as long as other watchers
+\& // with the default priority are receiving events.
+\& ev_idle_start (EV_A_ &idle);
+\& }
+\&
+\& static void
+\& idle_cb (EV_P_ ev_idle *w, int revents)
+\& {
+\& // actual processing
+\& read (STDIN_FILENO, ...);
+\&
+\& // have to start the I/O watcher again, as
+\& // we have handled the event
+\& ev_io_start (EV_P_ &io);
+\& }
+\&
+\& // initialisation
+\& ev_idle_init (&idle, idle_cb);
+\& ev_io_init (&io, io_cb, STDIN_FILENO, EV_READ);
+\& ev_io_start (EV_DEFAULT_ &io);
+.Ve
+.PP
+In the \*(L"real\*(R" world, it might also be beneficial to start a timer, so that
+low-priority connections can not be locked out forever under load. This
+enables your program to keep a lower latency for important connections
+during short periods of high load, while not completely locking out less
+important ones.
+.SH "WATCHER TYPES"
+.IX Header "WATCHER TYPES"
+This section describes each watcher in detail, but will not repeat
+information given in the last section. Any initialisation/set macros,
+functions and members specific to the watcher type are explained.
+.PP
+Members are additionally marked with either \fI[read\-only]\fR, meaning that,
+while the watcher is active, you can look at the member and expect some
+sensible content, but you must not modify it (you can modify it while the
+watcher is stopped to your hearts content), or \fI[read\-write]\fR, which
+means you can expect it to have some sensible content while the watcher
+is active, but you can also modify it. Modifying it may not do something
+sensible or take immediate effect (or do anything at all), but libev will
+not crash or malfunction in any way.
+.ie n .SS """ev_io"" \- is this file descriptor readable or writable?"
+.el .SS "\f(CWev_io\fP \- is this file descriptor readable or writable?"
+.IX Subsection "ev_io - is this file descriptor readable or writable?"
+I/O watchers check whether a file descriptor is readable or writable
+in each iteration of the event loop, or, more precisely, when reading
+would not block the process and writing would at least be able to write
+some data. This behaviour is called level-triggering because you keep
+receiving events as long as the condition persists. Remember you can stop
+the watcher if you don't want to act on the event and neither want to
+receive future events.
+.PP
+In general you can register as many read and/or write event watchers per
+fd as you want (as long as you don't confuse yourself). Setting all file
+descriptors to non-blocking mode is also usually a good idea (but not
+required if you know what you are doing).
+.PP
+Another thing you have to watch out for is that it is quite easy to
+receive \*(L"spurious\*(R" readiness notifications, that is, your callback might
+be called with \f(CW\*(C`EV_READ\*(C'\fR but a subsequent \f(CW\*(C`read\*(C'\fR(2) will actually block
+because there is no data. It is very easy to get into this situation even
+with a relatively standard program structure. Thus it is best to always
+use non-blocking I/O: An extra \f(CW\*(C`read\*(C'\fR(2) returning \f(CW\*(C`EAGAIN\*(C'\fR is far
+preferable to a program hanging until some data arrives.
+.PP
+If you cannot run the fd in non-blocking mode (for example you should
+not play around with an Xlib connection), then you have to separately
+re-test whether a file descriptor is really ready with a known-to-be good
+interface such as poll (fortunately in the case of Xlib, it already does
+this on its own, so its quite safe to use). Some people additionally
+use \f(CW\*(C`SIGALRM\*(C'\fR and an interval timer, just to be sure you won't block
+indefinitely.
+.PP
+But really, best use non-blocking mode.
+.PP
+\fIThe special problem of disappearing file descriptors\fR
+.IX Subsection "The special problem of disappearing file descriptors"
+.PP
+Some backends (e.g. kqueue, epoll) need to be told about closing a file
+descriptor (either due to calling \f(CW\*(C`close\*(C'\fR explicitly or any other means,
+such as \f(CW\*(C`dup2\*(C'\fR). The reason is that you register interest in some file
+descriptor, but when it goes away, the operating system will silently drop
+this interest. If another file descriptor with the same number then is
+registered with libev, there is no efficient way to see that this is, in
+fact, a different file descriptor.
+.PP
+To avoid having to explicitly tell libev about such cases, libev follows
+the following policy: Each time \f(CW\*(C`ev_io_set\*(C'\fR is being called, libev
+will assume that this is potentially a new file descriptor, otherwise
+it is assumed that the file descriptor stays the same. That means that
+you \fIhave\fR to call \f(CW\*(C`ev_io_set\*(C'\fR (or \f(CW\*(C`ev_io_init\*(C'\fR) when you change the
+descriptor even if the file descriptor number itself did not change.
+.PP
+This is how one would do it normally anyway, the important point is that
+the libev application should not optimise around libev but should leave
+optimisations to libev.
+.PP
+\fIThe special problem of dup'ed file descriptors\fR
+.IX Subsection "The special problem of dup'ed file descriptors"
+.PP
+Some backends (e.g. epoll), cannot register events for file descriptors,
+but only events for the underlying file descriptions. That means when you
+have \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors or weirder constellations, and register
+events for them, only one file descriptor might actually receive events.
+.PP
+There is no workaround possible except not registering events
+for potentially \f(CW\*(C`dup ()\*(C'\fR'ed file descriptors, or to resort to
+\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.PP
+\fIThe special problem of files\fR
+.IX Subsection "The special problem of files"
+.PP
+Many people try to use \f(CW\*(C`select\*(C'\fR (or libev) on file descriptors
+representing files, and expect it to become ready when their program
+doesn't block on disk accesses (which can take a long time on their own).
+.PP
+However, this cannot ever work in the \*(L"expected\*(R" way \- you get a readiness
+notification as soon as the kernel knows whether and how much data is
+there, and in the case of open files, that's always the case, so you
+always get a readiness notification instantly, and your read (or possibly
+write) will still block on the disk I/O.
+.PP
+Another way to view it is that in the case of sockets, pipes, character
+devices and so on, there is another party (the sender) that delivers data
+on its own, but in the case of files, there is no such thing: the disk
+will not send data on its own, simply because it doesn't know what you
+wish to read \- you would first have to request some data.
+.PP
+Since files are typically not-so-well supported by advanced notification
+mechanism, libev tries hard to emulate \s-1POSIX\s0 behaviour with respect
+to files, even though you should not use it. The reason for this is
+convenience: sometimes you want to watch \s-1STDIN\s0 or \s-1STDOUT,\s0 which is
+usually a tty, often a pipe, but also sometimes files or special devices
+(for example, \f(CW\*(C`epoll\*(C'\fR on Linux works with \fI/dev/random\fR but not with
+\&\fI/dev/urandom\fR), and even though the file might better be served with
+asynchronous I/O instead of with non-blocking I/O, it is still useful when
+it \*(L"just works\*(R" instead of freezing.
+.PP
+So avoid file descriptors pointing to files when you know it (e.g. use
+libeio), but use them when it is convenient, e.g. for \s-1STDIN/STDOUT,\s0 or
+when you rarely read from a file instead of from a socket, and want to
+reuse the same code path.
+.PP
+\fIThe special problem of fork\fR
+.IX Subsection "The special problem of fork"
+.PP
+Some backends (epoll, kqueue) do not support \f(CW\*(C`fork ()\*(C'\fR at all or exhibit
+useless behaviour. Libev fully supports fork, but needs to be told about
+it in the child if you want to continue to use it in the child.
+.PP
+To support fork in your child processes, you have to call \f(CW\*(C`ev_loop_fork
+()\*(C'\fR after a fork in the child, enable \f(CW\*(C`EVFLAG_FORKCHECK\*(C'\fR, or resort to
+\&\f(CW\*(C`EVBACKEND_SELECT\*(C'\fR or \f(CW\*(C`EVBACKEND_POLL\*(C'\fR.
+.PP
+\fIThe special problem of \s-1SIGPIPE\s0\fR
+.IX Subsection "The special problem of SIGPIPE"
+.PP
+While not really specific to libev, it is easy to forget about \f(CW\*(C`SIGPIPE\*(C'\fR:
+when writing to a pipe whose other end has been closed, your program gets
+sent a \s-1SIGPIPE,\s0 which, by default, aborts your program. For most programs
+this is sensible behaviour, for daemons, this is usually undesirable.
+.PP
+So when you encounter spurious, unexplained daemon exits, make sure you
+ignore \s-1SIGPIPE \s0(and maybe make sure you log the exit status of your daemon
+somewhere, as that would have given you a big clue).
+.PP
+\fIThe special problem of \fIaccept()\fIing when you can't\fR
+.IX Subsection "The special problem of accept()ing when you can't"
+.PP
+Many implementations of the \s-1POSIX \s0\f(CW\*(C`accept\*(C'\fR function (for example,
+found in post\-2004 Linux) have the peculiar behaviour of not removing a
+connection from the pending queue in all error cases.
+.PP
+For example, larger servers often run out of file descriptors (because
+of resource limits), causing \f(CW\*(C`accept\*(C'\fR to fail with \f(CW\*(C`ENFILE\*(C'\fR but not
+rejecting the connection, leading to libev signalling readiness on
+the next iteration again (the connection still exists after all), and
+typically causing the program to loop at 100% \s-1CPU\s0 usage.
+.PP
+Unfortunately, the set of errors that cause this issue differs between
+operating systems, there is usually little the app can do to remedy the
+situation, and no known thread-safe method of removing the connection to
+cope with overload is known (to me).
+.PP
+One of the easiest ways to handle this situation is to just ignore it
+\&\- when the program encounters an overload, it will just loop until the
+situation is over. While this is a form of busy waiting, no \s-1OS\s0 offers an
+event-based way to handle this situation, so it's the best one can do.
+.PP
+A better way to handle the situation is to log any errors other than
+\&\f(CW\*(C`EAGAIN\*(C'\fR and \f(CW\*(C`EWOULDBLOCK\*(C'\fR, making sure not to flood the log with such
+messages, and continue as usual, which at least gives the user an idea of
+what could be wrong (\*(L"raise the ulimit!\*(R"). For extra points one could stop
+the \f(CW\*(C`ev_io\*(C'\fR watcher on the listening fd \*(L"for a while\*(R", which reduces \s-1CPU\s0
+usage.
+.PP
+If your program is single-threaded, then you could also keep a dummy file
+descriptor for overload situations (e.g. by opening \fI/dev/null\fR), and
+when you run into \f(CW\*(C`ENFILE\*(C'\fR or \f(CW\*(C`EMFILE\*(C'\fR, close it, run \f(CW\*(C`accept\*(C'\fR,
+close that fd, and create a new dummy fd. This will gracefully refuse
+clients under typical overload conditions.
+.PP
+The last way to handle it is to simply log the error and \f(CW\*(C`exit\*(C'\fR, as
+is often done with \f(CW\*(C`malloc\*(C'\fR failures, but this results in an easy
+opportunity for a DoS attack.
+.PP
+\fIWatcher-Specific Functions\fR
+.IX Subsection "Watcher-Specific Functions"
+.IP "ev_io_init (ev_io *, callback, int fd, int events)" 4
+.IX Item "ev_io_init (ev_io *, callback, int fd, int events)"
+.PD 0
+.IP "ev_io_set (ev_io *, int fd, int events)" 4
+.IX Item "ev_io_set (ev_io *, int fd, int events)"
+.PD
+Configures an \f(CW\*(C`ev_io\*(C'\fR watcher. The \f(CW\*(C`fd\*(C'\fR is the file descriptor to
+receive events for and \f(CW\*(C`events\*(C'\fR is either \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or
+\&\f(CW\*(C`EV_READ | EV_WRITE\*(C'\fR, to express the desire to receive the given events.
+.IP "int fd [read\-only]" 4
+.IX Item "int fd [read-only]"
+The file descriptor being watched.
+.IP "int events [read\-only]" 4
+.IX Item "int events [read-only]"
+The events being watched.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Call \f(CW\*(C`stdin_readable_cb\*(C'\fR when \s-1STDIN_FILENO\s0 has become, well
+readable, but only once. Since it is likely line-buffered, you could
+attempt to read a whole line in the callback.
+.PP
+.Vb 6
+\& static void
+\& stdin_readable_cb (struct ev_loop *loop, ev_io *w, int revents)
+\& {
+\& ev_io_stop (loop, w);
+\& .. read from stdin here (or from w\->fd) and handle any I/O errors
+\& }
+\&
+\& ...
+\& struct ev_loop *loop = ev_default_init (0);
+\& ev_io stdin_readable;
+\& ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
+\& ev_io_start (loop, &stdin_readable);
+\& ev_run (loop, 0);
+.Ve
+.ie n .SS """ev_timer"" \- relative and optionally repeating timeouts"
+.el .SS "\f(CWev_timer\fP \- relative and optionally repeating timeouts"
+.IX Subsection "ev_timer - relative and optionally repeating timeouts"
+Timer watchers are simple relative timers that generate an event after a
+given time, and optionally repeating in regular intervals after that.
+.PP
+The timers are based on real time, that is, if you register an event that
+times out after an hour and you reset your system clock to January last
+year, it will still time out after (roughly) one hour. \*(L"Roughly\*(R" because
+detecting time jumps is hard, and some inaccuracies are unavoidable (the
+monotonic clock option helps a lot here).
+.PP
+The callback is guaranteed to be invoked only \fIafter\fR its timeout has
+passed (not \fIat\fR, so on systems with very low-resolution clocks this
+might introduce a small delay, see \*(L"the special problem of being too
+early\*(R", below). If multiple timers become ready during the same loop
+iteration then the ones with earlier time-out values are invoked before
+ones of the same priority with later time-out values (but this is no
+longer true when a callback calls \f(CW\*(C`ev_run\*(C'\fR recursively).
+.PP
+\fIBe smart about timeouts\fR
+.IX Subsection "Be smart about timeouts"
+.PP
+Many real-world problems involve some kind of timeout, usually for error
+recovery. A typical example is an \s-1HTTP\s0 request \- if the other side hangs,
+you want to raise some error after a while.
+.PP
+What follows are some ways to handle this problem, from obvious and
+inefficient to smart and efficient.
+.PP
+In the following, a 60 second activity timeout is assumed \- a timeout that
+gets reset to 60 seconds each time there is activity (e.g. each time some
+data or other life sign was received).
+.IP "1. Use a timer and stop, reinitialise and start it on activity." 4
+.IX Item "1. Use a timer and stop, reinitialise and start it on activity."
+This is the most obvious, but not the most simple way: In the beginning,
+start the watcher:
+.Sp
+.Vb 2
+\& ev_timer_init (timer, callback, 60., 0.);
+\& ev_timer_start (loop, timer);
+.Ve
+.Sp
+Then, each time there is some activity, \f(CW\*(C`ev_timer_stop\*(C'\fR it, initialise it
+and start it again:
+.Sp
+.Vb 3
+\& ev_timer_stop (loop, timer);
+\& ev_timer_set (timer, 60., 0.);
+\& ev_timer_start (loop, timer);
+.Ve
+.Sp
+This is relatively simple to implement, but means that each time there is
+some activity, libev will first have to remove the timer from its internal
+data structure and then add it again. Libev tries to be fast, but it's
+still not a constant-time operation.
+.ie n .IP "2. Use a timer and re-start it with ""ev_timer_again"" inactivity." 4
+.el .IP "2. Use a timer and re-start it with \f(CWev_timer_again\fR inactivity." 4
+.IX Item "2. Use a timer and re-start it with ev_timer_again inactivity."
+This is the easiest way, and involves using \f(CW\*(C`ev_timer_again\*(C'\fR instead of
+\&\f(CW\*(C`ev_timer_start\*(C'\fR.
+.Sp
+To implement this, configure an \f(CW\*(C`ev_timer\*(C'\fR with a \f(CW\*(C`repeat\*(C'\fR value
+of \f(CW60\fR and then call \f(CW\*(C`ev_timer_again\*(C'\fR at start and each time you
+successfully read or write some data. If you go into an idle state where
+you do not expect data to travel on the socket, you can \f(CW\*(C`ev_timer_stop\*(C'\fR
+the timer, and \f(CW\*(C`ev_timer_again\*(C'\fR will automatically restart it if need be.
+.Sp
+That means you can ignore both the \f(CW\*(C`ev_timer_start\*(C'\fR function and the
+\&\f(CW\*(C`after\*(C'\fR argument to \f(CW\*(C`ev_timer_set\*(C'\fR, and only ever use the \f(CW\*(C`repeat\*(C'\fR
+member and \f(CW\*(C`ev_timer_again\*(C'\fR.
+.Sp
+At start:
+.Sp
+.Vb 3
+\& ev_init (timer, callback);
+\& timer\->repeat = 60.;
+\& ev_timer_again (loop, timer);
+.Ve
+.Sp
+Each time there is some activity:
+.Sp
+.Vb 1
+\& ev_timer_again (loop, timer);
+.Ve
+.Sp
+It is even possible to change the time-out on the fly, regardless of
+whether the watcher is active or not:
+.Sp
+.Vb 2
+\& timer\->repeat = 30.;
+\& ev_timer_again (loop, timer);
+.Ve
+.Sp
+This is slightly more efficient then stopping/starting the timer each time
+you want to modify its timeout value, as libev does not have to completely
+remove and re-insert the timer from/into its internal data structure.
+.Sp
+It is, however, even simpler than the \*(L"obvious\*(R" way to do it.
+.IP "3. Let the timer time out, but then re-arm it as required." 4
+.IX Item "3. Let the timer time out, but then re-arm it as required."
+This method is more tricky, but usually most efficient: Most timeouts are
+relatively long compared to the intervals between other activity \- in
+our example, within 60 seconds, there are usually many I/O events with
+associated activity resets.
+.Sp
+In this case, it would be more efficient to leave the \f(CW\*(C`ev_timer\*(C'\fR alone,
+but remember the time of last activity, and check for a real timeout only
+within the callback:
+.Sp
+.Vb 3
+\& ev_tstamp timeout = 60.;
+\& ev_tstamp last_activity; // time of last activity
+\& ev_timer timer;
+\&
+\& static void
+\& callback (EV_P_ ev_timer *w, int revents)
+\& {
+\& // calculate when the timeout would happen
+\& ev_tstamp after = last_activity \- ev_now (EV_A) + timeout;
+\&
+\& // if negative, it means we the timeout already occurred
+\& if (after < 0.)
+\& {
+\& // timeout occurred, take action
+\& }
+\& else
+\& {
+\& // callback was invoked, but there was some recent
+\& // activity. simply restart the timer to time out
+\& // after "after" seconds, which is the earliest time
+\& // the timeout can occur.
+\& ev_timer_set (w, after, 0.);
+\& ev_timer_start (EV_A_ w);
+\& }
+\& }
+.Ve
+.Sp
+To summarise the callback: first calculate in how many seconds the
+timeout will occur (by calculating the absolute time when it would occur,
+\&\f(CW\*(C`last_activity + timeout\*(C'\fR, and subtracting the current time, \f(CW\*(C`ev_now
+(EV_A)\*(C'\fR from that).
+.Sp
+If this value is negative, then we are already past the timeout, i.e. we
+timed out, and need to do whatever is needed in this case.
+.Sp
+Otherwise, we now the earliest time at which the timeout would trigger,
+and simply start the timer with this timeout value.
+.Sp
+In other words, each time the callback is invoked it will check whether
+the timeout occurred. If not, it will simply reschedule itself to check
+again at the earliest time it could time out. Rinse. Repeat.
+.Sp
+This scheme causes more callback invocations (about one every 60 seconds
+minus half the average time between activity), but virtually no calls to
+libev to change the timeout.
+.Sp
+To start the machinery, simply initialise the watcher and set
+\&\f(CW\*(C`last_activity\*(C'\fR to the current time (meaning there was some activity just
+now), then call the callback, which will \*(L"do the right thing\*(R" and start
+the timer:
+.Sp
+.Vb 3
+\& last_activity = ev_now (EV_A);
+\& ev_init (&timer, callback);
+\& callback (EV_A_ &timer, 0);
+.Ve
+.Sp
+When there is some activity, simply store the current time in
+\&\f(CW\*(C`last_activity\*(C'\fR, no libev calls at all:
+.Sp
+.Vb 2
+\& if (activity detected)
+\& last_activity = ev_now (EV_A);
+.Ve
+.Sp
+When your timeout value changes, then the timeout can be changed by simply
+providing a new value, stopping the timer and calling the callback, which
+will again do the right thing (for example, time out immediately :).
+.Sp
+.Vb 3
+\& timeout = new_value;
+\& ev_timer_stop (EV_A_ &timer);
+\& callback (EV_A_ &timer, 0);
+.Ve
+.Sp
+This technique is slightly more complex, but in most cases where the
+time-out is unlikely to be triggered, much more efficient.
+.IP "4. Wee, just use a double-linked list for your timeouts." 4
+.IX Item "4. Wee, just use a double-linked list for your timeouts."
+If there is not one request, but many thousands (millions...), all
+employing some kind of timeout with the same timeout value, then one can
+do even better:
+.Sp
+When starting the timeout, calculate the timeout value and put the timeout
+at the \fIend\fR of the list.
+.Sp
+Then use an \f(CW\*(C`ev_timer\*(C'\fR to fire when the timeout at the \fIbeginning\fR of
+the list is expected to fire (for example, using the technique #3).
+.Sp
+When there is some activity, remove the timer from the list, recalculate
+the timeout, append it to the end of the list again, and make sure to
+update the \f(CW\*(C`ev_timer\*(C'\fR if it was taken from the beginning of the list.
+.Sp
+This way, one can manage an unlimited number of timeouts in O(1) time for
+starting, stopping and updating the timers, at the expense of a major
+complication, and having to use a constant timeout. The constant timeout
+ensures that the list stays sorted.
+.PP
+So which method the best?
+.PP
+Method #2 is a simple no-brain-required solution that is adequate in most
+situations. Method #3 requires a bit more thinking, but handles many cases
+better, and isn't very complicated either. In most case, choosing either
+one is fine, with #3 being better in typical situations.
+.PP
+Method #1 is almost always a bad idea, and buys you nothing. Method #4 is
+rather complicated, but extremely efficient, something that really pays
+off after the first million or so of active timers, i.e. it's usually
+overkill :)
+.PP
+\fIThe special problem of being too early\fR
+.IX Subsection "The special problem of being too early"
+.PP
+If you ask a timer to call your callback after three seconds, then
+you expect it to be invoked after three seconds \- but of course, this
+cannot be guaranteed to infinite precision. Less obviously, it cannot be
+guaranteed to any precision by libev \- imagine somebody suspending the
+process with a \s-1STOP\s0 signal for a few hours for example.
+.PP
+So, libev tries to invoke your callback as soon as possible \fIafter\fR the
+delay has occurred, but cannot guarantee this.
+.PP
+A less obvious failure mode is calling your callback too early: many event
+loops compare timestamps with a \*(L"elapsed delay >= requested delay\*(R", but
+this can cause your callback to be invoked much earlier than you would
+expect.
+.PP
+To see why, imagine a system with a clock that only offers full second
+resolution (think windows if you can't come up with a broken enough \s-1OS\s0
+yourself). If you schedule a one-second timer at the time 500.9, then the
+event loop will schedule your timeout to elapse at a system time of 500
+(500.9 truncated to the resolution) + 1, or 501.
+.PP
+If an event library looks at the timeout 0.1s later, it will see \*(L"501 >=
+501\*(R" and invoke the callback 0.1s after it was started, even though a
+one-second delay was requested \- this is being \*(L"too early\*(R", despite best
+intentions.
+.PP
+This is the reason why libev will never invoke the callback if the elapsed
+delay equals the requested delay, but only when the elapsed delay is
+larger than the requested delay. In the example above, libev would only invoke
+the callback at system time 502, or 1.1s after the timer was started.
+.PP
+So, while libev cannot guarantee that your callback will be invoked
+exactly when requested, it \fIcan\fR and \fIdoes\fR guarantee that the requested
+delay has actually elapsed, or in other words, it always errs on the \*(L"too
+late\*(R" side of things.
+.PP
+\fIThe special problem of time updates\fR
+.IX Subsection "The special problem of time updates"
+.PP
+Establishing the current time is a costly operation (it usually takes
+at least one system call): \s-1EV\s0 therefore updates its idea of the current
+time only before and after \f(CW\*(C`ev_run\*(C'\fR collects new events, which causes a
+growing difference between \f(CW\*(C`ev_now ()\*(C'\fR and \f(CW\*(C`ev_time ()\*(C'\fR when handling
+lots of events in one iteration.
+.PP
+The relative timeouts are calculated relative to the \f(CW\*(C`ev_now ()\*(C'\fR
+time. This is usually the right thing as this timestamp refers to the time
+of the event triggering whatever timeout you are modifying/starting. If
+you suspect event processing to be delayed and you \fIneed\fR to base the
+timeout on the current time, use something like the following to adjust
+for it:
+.PP
+.Vb 1
+\& ev_timer_set (&timer, after + (ev_time () \- ev_now ()), 0.);
+.Ve
+.PP
+If the event loop is suspended for a long time, you can also force an
+update of the time returned by \f(CW\*(C`ev_now ()\*(C'\fR by calling \f(CW\*(C`ev_now_update
+()\*(C'\fR, although that will push the event time of all outstanding events
+further into the future.
+.PP
+\fIThe special problem of unsynchronised clocks\fR
+.IX Subsection "The special problem of unsynchronised clocks"
+.PP
+Modern systems have a variety of clocks \- libev itself uses the normal
+\&\*(L"wall clock\*(R" clock and, if available, the monotonic clock (to avoid time
+jumps).
+.PP
+Neither of these clocks is synchronised with each other or any other clock
+on the system, so \f(CW\*(C`ev_time ()\*(C'\fR might return a considerably different time
+than \f(CW\*(C`gettimeofday ()\*(C'\fR or \f(CW\*(C`time ()\*(C'\fR. On a GNU/Linux system, for example,
+a call to \f(CW\*(C`gettimeofday\*(C'\fR might return a second count that is one higher
+than a directly following call to \f(CW\*(C`time\*(C'\fR.
+.PP
+The moral of this is to only compare libev-related timestamps with
+\&\f(CW\*(C`ev_time ()\*(C'\fR and \f(CW\*(C`ev_now ()\*(C'\fR, at least if you want better precision than
+a second or so.
+.PP
+One more problem arises due to this lack of synchronisation: if libev uses
+the system monotonic clock and you compare timestamps from \f(CW\*(C`ev_time\*(C'\fR
+or \f(CW\*(C`ev_now\*(C'\fR from when you started your timer and when your callback is
+invoked, you will find that sometimes the callback is a bit \*(L"early\*(R".
+.PP
+This is because \f(CW\*(C`ev_timer\*(C'\fRs work in real time, not wall clock time, so
+libev makes sure your callback is not invoked before the delay happened,
+\&\fImeasured according to the real time\fR, not the system clock.
+.PP
+If your timeouts are based on a physical timescale (e.g. \*(L"time out this
+connection after 100 seconds\*(R") then this shouldn't bother you as it is
+exactly the right behaviour.
+.PP
+If you want to compare wall clock/system timestamps to your timers, then
+you need to use \f(CW\*(C`ev_periodic\*(C'\fRs, as these are based on the wall clock
+time, where your comparisons will always generate correct results.
+.PP
+\fIThe special problems of suspended animation\fR
+.IX Subsection "The special problems of suspended animation"
+.PP
+When you leave the server world it is quite customary to hit machines that
+can suspend/hibernate \- what happens to the clocks during such a suspend?
+.PP
+Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes
+all processes, while the clocks (\f(CW\*(C`times\*(C'\fR, \f(CW\*(C`CLOCK_MONOTONIC\*(C'\fR) continue
+to run until the system is suspended, but they will not advance while the
+system is suspended. That means, on resume, it will be as if the program
+was frozen for a few seconds, but the suspend time will not be counted
+towards \f(CW\*(C`ev_timer\*(C'\fR when a monotonic clock source is used. The real time
+clock advanced as expected, but if it is used as sole clocksource, then a
+long suspend would be detected as a time jump by libev, and timers would
+be adjusted accordingly.
+.PP
+I would not be surprised to see different behaviour in different between
+operating systems, \s-1OS\s0 versions or even different hardware.
+.PP
+The other form of suspend (job control, or sending a \s-1SIGSTOP\s0) will see a
+time jump in the monotonic clocks and the realtime clock. If the program
+is suspended for a very long time, and monotonic clock sources are in use,
+then you can expect \f(CW\*(C`ev_timer\*(C'\fRs to expire as the full suspension time
+will be counted towards the timers. When no monotonic clock source is in
+use, then libev will again assume a timejump and adjust accordingly.
+.PP
+It might be beneficial for this latter case to call \f(CW\*(C`ev_suspend\*(C'\fR
+and \f(CW\*(C`ev_resume\*(C'\fR in code that handles \f(CW\*(C`SIGTSTP\*(C'\fR, to at least get
+deterministic behaviour in this case (you can do nothing against
+\&\f(CW\*(C`SIGSTOP\*(C'\fR).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)" 4
+.IX Item "ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)"
+.PD 0
+.IP "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)" 4
+.IX Item "ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)"
+.PD
+Configure the timer to trigger after \f(CW\*(C`after\*(C'\fR seconds. If \f(CW\*(C`repeat\*(C'\fR
+is \f(CW0.\fR, then it will automatically be stopped once the timeout is
+reached. If it is positive, then the timer will automatically be
+configured to trigger again \f(CW\*(C`repeat\*(C'\fR seconds later, again, and again,
+until stopped manually.
+.Sp
+The timer itself will do a best-effort at avoiding drift, that is, if
+you configure a timer to trigger every 10 seconds, then it will normally
+trigger at exactly 10 second intervals. If, however, your program cannot
+keep up with the timer (because it takes longer than those 10 seconds to
+do stuff) the timer will not fire more than once per event loop iteration.
+.IP "ev_timer_again (loop, ev_timer *)" 4
+.IX Item "ev_timer_again (loop, ev_timer *)"
+This will act as if the timer timed out, and restarts it again if it is
+repeating. It basically works like calling \f(CW\*(C`ev_timer_stop\*(C'\fR, updating the
+timeout to the \f(CW\*(C`repeat\*(C'\fR value and calling \f(CW\*(C`ev_timer_start\*(C'\fR.
+.Sp
+The exact semantics are as in the following rules, all of which will be
+applied to the watcher:
+.RS 4
+.IP "If the timer is pending, the pending status is always cleared." 4
+.IX Item "If the timer is pending, the pending status is always cleared."
+.PD 0
+.IP "If the timer is started but non-repeating, stop it (as if it timed out, without invoking it)." 4
+.IX Item "If the timer is started but non-repeating, stop it (as if it timed out, without invoking it)."
+.ie n .IP "If the timer is repeating, make the ""repeat"" value the new timeout and start the timer, if necessary." 4
+.el .IP "If the timer is repeating, make the \f(CWrepeat\fR value the new timeout and start the timer, if necessary." 4
+.IX Item "If the timer is repeating, make the repeat value the new timeout and start the timer, if necessary."
+.RE
+.RS 4
+.PD
+.Sp
+This sounds a bit complicated, see \*(L"Be smart about timeouts\*(R", above, for a
+usage example.
+.RE
+.IP "ev_tstamp ev_timer_remaining (loop, ev_timer *)" 4
+.IX Item "ev_tstamp ev_timer_remaining (loop, ev_timer *)"
+Returns the remaining time until a timer fires. If the timer is active,
+then this time is relative to the current event loop time, otherwise it's
+the timeout value currently configured.
+.Sp
+That is, after an \f(CW\*(C`ev_timer_set (w, 5, 7)\*(C'\fR, \f(CW\*(C`ev_timer_remaining\*(C'\fR returns
+\&\f(CW5\fR. When the timer is started and one second passes, \f(CW\*(C`ev_timer_remaining\*(C'\fR
+will return \f(CW4\fR. When the timer expires and is restarted, it will return
+roughly \f(CW7\fR (likely slightly less as callback invocation takes some time,
+too), and so on.
+.IP "ev_tstamp repeat [read\-write]" 4
+.IX Item "ev_tstamp repeat [read-write]"
+The current \f(CW\*(C`repeat\*(C'\fR value. Will be used each time the watcher times out
+or \f(CW\*(C`ev_timer_again\*(C'\fR is called, and determines the next timeout (if any),
+which is also when any modifications are taken into account.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Create a timer that fires after 60 seconds.
+.PP
+.Vb 5
+\& static void
+\& one_minute_cb (struct ev_loop *loop, ev_timer *w, int revents)
+\& {
+\& .. one minute over, w is actually stopped right here
+\& }
+\&
+\& ev_timer mytimer;
+\& ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
+\& ev_timer_start (loop, &mytimer);
+.Ve
+.PP
+Example: Create a timeout timer that times out after 10 seconds of
+inactivity.
+.PP
+.Vb 5
+\& static void
+\& timeout_cb (struct ev_loop *loop, ev_timer *w, int revents)
+\& {
+\& .. ten seconds without any activity
+\& }
+\&
+\& ev_timer mytimer;
+\& ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
+\& ev_timer_again (&mytimer); /* start timer */
+\& ev_run (loop, 0);
+\&
+\& // and in some piece of code that gets executed on any "activity":
+\& // reset the timeout to start ticking again at 10 seconds
+\& ev_timer_again (&mytimer);
+.Ve
+.ie n .SS """ev_periodic"" \- to cron or not to cron?"
+.el .SS "\f(CWev_periodic\fP \- to cron or not to cron?"
+.IX Subsection "ev_periodic - to cron or not to cron?"
+Periodic watchers are also timers of a kind, but they are very versatile
+(and unfortunately a bit complex).
+.PP
+Unlike \f(CW\*(C`ev_timer\*(C'\fR, periodic watchers are not based on real time (or
+relative time, the physical time that passes) but on wall clock time
+(absolute time, the thing you can read on your calendar or clock). The
+difference is that wall clock time can run faster or slower than real
+time, and time jumps are not uncommon (e.g. when you adjust your
+wrist-watch).
+.PP
+You can tell a periodic watcher to trigger after some specific point
+in time: for example, if you tell a periodic watcher to trigger \*(L"in 10
+seconds\*(R" (by specifying e.g. \f(CW\*(C`ev_now () + 10.\*(C'\fR, that is, an absolute time
+not a delay) and then reset your system clock to January of the previous
+year, then it will take a year or more to trigger the event (unlike an
+\&\f(CW\*(C`ev_timer\*(C'\fR, which would still trigger roughly 10 seconds after starting
+it, as it uses a relative timeout).
+.PP
+\&\f(CW\*(C`ev_periodic\*(C'\fR watchers can also be used to implement vastly more complex
+timers, such as triggering an event on each \*(L"midnight, local time\*(R", or
+other complicated rules. This cannot be done with \f(CW\*(C`ev_timer\*(C'\fR watchers, as
+those cannot react to time jumps.
+.PP
+As with timers, the callback is guaranteed to be invoked only when the
+point in time where it is supposed to trigger has passed. If multiple
+timers become ready during the same loop iteration then the ones with
+earlier time-out values are invoked before ones with later time-out values
+(but this is no longer true when a callback calls \f(CW\*(C`ev_run\*(C'\fR recursively).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" 4
+.IX Item "ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)"
+.PD 0
+.IP "ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)" 4
+.IX Item "ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)"
+.PD
+Lots of arguments, let's sort it out... There are basically three modes of
+operation, and we will explain them from simplest to most complex:
+.RS 4
+.IP "\(bu" 4
+absolute timer (offset = absolute time, interval = 0, reschedule_cb = 0)
+.Sp
+In this configuration the watcher triggers an event after the wall clock
+time \f(CW\*(C`offset\*(C'\fR has passed. It will not repeat and will not adjust when a
+time jump occurs, that is, if it is to be run at January 1st 2011 then it
+will be stopped and invoked when the system clock reaches or surpasses
+this point in time.
+.IP "\(bu" 4
+repeating interval timer (offset = offset within interval, interval > 0, reschedule_cb = 0)
+.Sp
+In this mode the watcher will always be scheduled to time out at the next
+\&\f(CW\*(C`offset + N * interval\*(C'\fR time (for some integer N, which can also be
+negative) and then repeat, regardless of any time jumps. The \f(CW\*(C`offset\*(C'\fR
+argument is merely an offset into the \f(CW\*(C`interval\*(C'\fR periods.
+.Sp
+This can be used to create timers that do not drift with respect to the
+system clock, for example, here is an \f(CW\*(C`ev_periodic\*(C'\fR that triggers each
+hour, on the hour (with respect to \s-1UTC\s0):
+.Sp
+.Vb 1
+\& ev_periodic_set (&periodic, 0., 3600., 0);
+.Ve
+.Sp
+This doesn't mean there will always be 3600 seconds in between triggers,
+but only that the callback will be called when the system time shows a
+full hour (\s-1UTC\s0), or more correctly, when the system time is evenly divisible
+by 3600.
+.Sp
+Another way to think about it (for the mathematically inclined) is that
+\&\f(CW\*(C`ev_periodic\*(C'\fR will try to run the callback in this mode at the next possible
+time where \f(CW\*(C`time = offset (mod interval)\*(C'\fR, regardless of any time jumps.
+.Sp
+The \f(CW\*(C`interval\*(C'\fR \fI\s-1MUST\s0\fR be positive, and for numerical stability, the
+interval value should be higher than \f(CW\*(C`1/8192\*(C'\fR (which is around 100
+microseconds) and \f(CW\*(C`offset\*(C'\fR should be higher than \f(CW0\fR and should have
+at most a similar magnitude as the current time (say, within a factor of
+ten). Typical values for offset are, in fact, \f(CW0\fR or something between
+\&\f(CW0\fR and \f(CW\*(C`interval\*(C'\fR, which is also the recommended range.
+.Sp
+Note also that there is an upper limit to how often a timer can fire (\s-1CPU\s0
+speed for example), so if \f(CW\*(C`interval\*(C'\fR is very small then timing stability
+will of course deteriorate. Libev itself tries to be exact to be about one
+millisecond (if the \s-1OS\s0 supports it and the machine is fast enough).
+.IP "\(bu" 4
+manual reschedule mode (offset ignored, interval ignored, reschedule_cb = callback)
+.Sp
+In this mode the values for \f(CW\*(C`interval\*(C'\fR and \f(CW\*(C`offset\*(C'\fR are both being
+ignored. Instead, each time the periodic watcher gets scheduled, the
+reschedule callback will be called with the watcher as first, and the
+current time as second argument.
+.Sp
+\&\s-1NOTE: \s0\fIThis callback \s-1MUST NOT\s0 stop or destroy any periodic watcher, ever,
+or make \s-1ANY\s0 other event loop modifications whatsoever, unless explicitly
+allowed by documentation here\fR.
+.Sp
+If you need to stop it, return \f(CW\*(C`now + 1e30\*(C'\fR (or so, fudge fudge) and stop
+it afterwards (e.g. by starting an \f(CW\*(C`ev_prepare\*(C'\fR watcher, which is the
+only event loop modification you are allowed to do).
+.Sp
+The callback prototype is \f(CW\*(C`ev_tstamp (*reschedule_cb)(ev_periodic
+*w, ev_tstamp now)\*(C'\fR, e.g.:
+.Sp
+.Vb 5
+\& static ev_tstamp
+\& my_rescheduler (ev_periodic *w, ev_tstamp now)
+\& {
+\& return now + 60.;
+\& }
+.Ve
+.Sp
+It must return the next time to trigger, based on the passed time value
+(that is, the lowest time value larger than to the second argument). It
+will usually be called just before the callback will be triggered, but
+might be called at other times, too.
+.Sp
+\&\s-1NOTE: \s0\fIThis callback must always return a time that is higher than or
+equal to the passed \f(CI\*(C`now\*(C'\fI value\fR.
+.Sp
+This can be used to create very complex timers, such as a timer that
+triggers on \*(L"next midnight, local time\*(R". To do this, you would calculate the
+next midnight after \f(CW\*(C`now\*(C'\fR and return the timestamp value for this. How
+you do this is, again, up to you (but it is not trivial, which is the main
+reason I omitted it as an example).
+.RE
+.RS 4
+.RE
+.IP "ev_periodic_again (loop, ev_periodic *)" 4
+.IX Item "ev_periodic_again (loop, ev_periodic *)"
+Simply stops and restarts the periodic watcher again. This is only useful
+when you changed some parameters or the reschedule callback would return
+a different time than the last time it was called (e.g. in a crond like
+program when the crontabs have changed).
+.IP "ev_tstamp ev_periodic_at (ev_periodic *)" 4
+.IX Item "ev_tstamp ev_periodic_at (ev_periodic *)"
+When active, returns the absolute time that the watcher is supposed
+to trigger next. This is not the same as the \f(CW\*(C`offset\*(C'\fR argument to
+\&\f(CW\*(C`ev_periodic_set\*(C'\fR, but indeed works even in interval and manual
+rescheduling modes.
+.IP "ev_tstamp offset [read\-write]" 4
+.IX Item "ev_tstamp offset [read-write]"
+When repeating, this contains the offset value, otherwise this is the
+absolute point in time (the \f(CW\*(C`offset\*(C'\fR value passed to \f(CW\*(C`ev_periodic_set\*(C'\fR,
+although libev might modify this value for better numerical stability).
+.Sp
+Can be modified any time, but changes only take effect when the periodic
+timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
+.IP "ev_tstamp interval [read\-write]" 4
+.IX Item "ev_tstamp interval [read-write]"
+The current interval value. Can be modified any time, but changes only
+take effect when the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being
+called.
+.IP "ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read\-write]" 4
+.IX Item "ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read-write]"
+The current reschedule callback, or \f(CW0\fR, if this functionality is
+switched off. Can be changed any time, but changes only take effect when
+the periodic timer fires or \f(CW\*(C`ev_periodic_again\*(C'\fR is being called.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Call a callback every hour, or, more precisely, whenever the
+system time is divisible by 3600. The callback invocation times have
+potentially a lot of jitter, but good long-term stability.
+.PP
+.Vb 5
+\& static void
+\& clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
+\& {
+\& ... its now a full hour (UTC, or TAI or whatever your clock follows)
+\& }
+\&
+\& ev_periodic hourly_tick;
+\& ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
+\& ev_periodic_start (loop, &hourly_tick);
+.Ve
+.PP
+Example: The same as above, but use a reschedule callback to do it:
+.PP
+.Vb 1
+\& #include <math.h>
+\&
+\& static ev_tstamp
+\& my_scheduler_cb (ev_periodic *w, ev_tstamp now)
+\& {
+\& return now + (3600. \- fmod (now, 3600.));
+\& }
+\&
+\& ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
+.Ve
+.PP
+Example: Call a callback every hour, starting now:
+.PP
+.Vb 4
+\& ev_periodic hourly_tick;
+\& ev_periodic_init (&hourly_tick, clock_cb,
+\& fmod (ev_now (loop), 3600.), 3600., 0);
+\& ev_periodic_start (loop, &hourly_tick);
+.Ve
+.ie n .SS """ev_signal"" \- signal me when a signal gets signalled!"
+.el .SS "\f(CWev_signal\fP \- signal me when a signal gets signalled!"
+.IX Subsection "ev_signal - signal me when a signal gets signalled!"
+Signal watchers will trigger an event when the process receives a specific
+signal one or more times. Even though signals are very asynchronous, libev
+will try its best to deliver signals synchronously, i.e. as part of the
+normal event processing, like any other event.
+.PP
+If you want signals to be delivered truly asynchronously, just use
+\&\f(CW\*(C`sigaction\*(C'\fR as you would do without libev and forget about sharing
+the signal. You can even use \f(CW\*(C`ev_async\*(C'\fR from a signal handler to
+synchronously wake up an event loop.
+.PP
+You can configure as many watchers as you like for the same signal, but
+only within the same loop, i.e. you can watch for \f(CW\*(C`SIGINT\*(C'\fR in your
+default loop and for \f(CW\*(C`SIGIO\*(C'\fR in another loop, but you cannot watch for
+\&\f(CW\*(C`SIGINT\*(C'\fR in both the default loop and another loop at the same time. At
+the moment, \f(CW\*(C`SIGCHLD\*(C'\fR is permanently tied to the default loop.
+.PP
+Only after the first watcher for a signal is started will libev actually
+register something with the kernel. It thus coexists with your own signal
+handlers as long as you don't register any with libev for the same signal.
+.PP
+If possible and supported, libev will install its handlers with
+\&\f(CW\*(C`SA_RESTART\*(C'\fR (or equivalent) behaviour enabled, so system calls should
+not be unduly interrupted. If you have a problem with system calls getting
+interrupted by signals you can block all signals in an \f(CW\*(C`ev_check\*(C'\fR watcher
+and unblock them in an \f(CW\*(C`ev_prepare\*(C'\fR watcher.
+.PP
+\fIThe special problem of inheritance over fork/execve/pthread_create\fR
+.IX Subsection "The special problem of inheritance over fork/execve/pthread_create"
+.PP
+Both the signal mask (\f(CW\*(C`sigprocmask\*(C'\fR) and the signal disposition
+(\f(CW\*(C`sigaction\*(C'\fR) are unspecified after starting a signal watcher (and after
+stopping it again), that is, libev might or might not block the signal,
+and might or might not set or restore the installed signal handler (but
+see \f(CW\*(C`EVFLAG_NOSIGMASK\*(C'\fR).
+.PP
+While this does not matter for the signal disposition (libev never
+sets signals to \f(CW\*(C`SIG_IGN\*(C'\fR, so handlers will be reset to \f(CW\*(C`SIG_DFL\*(C'\fR on
+\&\f(CW\*(C`execve\*(C'\fR), this matters for the signal mask: many programs do not expect
+certain signals to be blocked.
+.PP
+This means that before calling \f(CW\*(C`exec\*(C'\fR (from the child) you should reset
+the signal mask to whatever \*(L"default\*(R" you expect (all clear is a good
+choice usually).
+.PP
+The simplest way to ensure that the signal mask is reset in the child is
+to install a fork handler with \f(CW\*(C`pthread_atfork\*(C'\fR that resets it. That will
+catch fork calls done by libraries (such as the libc) as well.
+.PP
+In current versions of libev, the signal will not be blocked indefinitely
+unless you use the \f(CW\*(C`signalfd\*(C'\fR \s-1API \s0(\f(CW\*(C`EV_SIGNALFD\*(C'\fR). While this reduces
+the window of opportunity for problems, it will not go away, as libev
+\&\fIhas\fR to modify the signal mask, at least temporarily.
+.PP
+So I can't stress this enough: \fIIf you do not reset your signal mask when
+you expect it to be empty, you have a race condition in your code\fR. This
+is not a libev-specific thing, this is true for most event libraries.
+.PP
+\fIThe special problem of threads signal handling\fR
+.IX Subsection "The special problem of threads signal handling"
+.PP
+\&\s-1POSIX\s0 threads has problematic signal handling semantics, specifically,
+a lot of functionality (sigfd, sigwait etc.) only really works if all
+threads in a process block signals, which is hard to achieve.
+.PP
+When you want to use sigwait (or mix libev signal handling with your own
+for the same signals), you can tackle this problem by globally blocking
+all signals before creating any threads (or creating them with a fully set
+sigprocmask) and also specifying the \f(CW\*(C`EVFLAG_NOSIGMASK\*(C'\fR when creating
+loops. Then designate one thread as \*(L"signal receiver thread\*(R" which handles
+these signals. You can pass on any signals that libev might be interested
+in by calling \f(CW\*(C`ev_feed_signal\*(C'\fR.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_signal_init (ev_signal *, callback, int signum)" 4
+.IX Item "ev_signal_init (ev_signal *, callback, int signum)"
+.PD 0
+.IP "ev_signal_set (ev_signal *, int signum)" 4
+.IX Item "ev_signal_set (ev_signal *, int signum)"
+.PD
+Configures the watcher to trigger on the given signal number (usually one
+of the \f(CW\*(C`SIGxxx\*(C'\fR constants).
+.IP "int signum [read\-only]" 4
+.IX Item "int signum [read-only]"
+The signal the watcher watches out for.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Try to exit cleanly on \s-1SIGINT.\s0
+.PP
+.Vb 5
+\& static void
+\& sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
+\& {
+\& ev_break (loop, EVBREAK_ALL);
+\& }
+\&
+\& ev_signal signal_watcher;
+\& ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
+\& ev_signal_start (loop, &signal_watcher);
+.Ve
+.ie n .SS """ev_child"" \- watch out for process status changes"
+.el .SS "\f(CWev_child\fP \- watch out for process status changes"
+.IX Subsection "ev_child - watch out for process status changes"
+Child watchers trigger when your process receives a \s-1SIGCHLD\s0 in response to
+some child status changes (most typically when a child of yours dies or
+exits). It is permissible to install a child watcher \fIafter\fR the child
+has been forked (which implies it might have already exited), as long
+as the event loop isn't entered (or is continued from a watcher), i.e.,
+forking and then immediately registering a watcher for the child is fine,
+but forking and registering a watcher a few event loop iterations later or
+in the next callback invocation is not.
+.PP
+Only the default event loop is capable of handling signals, and therefore
+you can only register child watchers in the default event loop.
+.PP
+Due to some design glitches inside libev, child watchers will always be
+handled at maximum priority (their priority is set to \f(CW\*(C`EV_MAXPRI\*(C'\fR by
+libev)
+.PP
+\fIProcess Interaction\fR
+.IX Subsection "Process Interaction"
+.PP
+Libev grabs \f(CW\*(C`SIGCHLD\*(C'\fR as soon as the default event loop is
+initialised. This is necessary to guarantee proper behaviour even if the
+first child watcher is started after the child exits. The occurrence
+of \f(CW\*(C`SIGCHLD\*(C'\fR is recorded asynchronously, but child reaping is done
+synchronously as part of the event loop processing. Libev always reaps all
+children, even ones not watched.
+.PP
+\fIOverriding the Built-In Processing\fR
+.IX Subsection "Overriding the Built-In Processing"
+.PP
+Libev offers no special support for overriding the built-in child
+processing, but if your application collides with libev's default child
+handler, you can override it easily by installing your own handler for
+\&\f(CW\*(C`SIGCHLD\*(C'\fR after initialising the default loop, and making sure the
+default loop never gets destroyed. You are encouraged, however, to use an
+event-based approach to child reaping and thus use libev's support for
+that, so other libev users can use \f(CW\*(C`ev_child\*(C'\fR watchers freely.
+.PP
+\fIStopping the Child Watcher\fR
+.IX Subsection "Stopping the Child Watcher"
+.PP
+Currently, the child watcher never gets stopped, even when the
+child terminates, so normally one needs to stop the watcher in the
+callback. Future versions of libev might stop the watcher automatically
+when a child exit is detected (calling \f(CW\*(C`ev_child_stop\*(C'\fR twice is not a
+problem).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_child_init (ev_child *, callback, int pid, int trace)" 4
+.IX Item "ev_child_init (ev_child *, callback, int pid, int trace)"
+.PD 0
+.IP "ev_child_set (ev_child *, int pid, int trace)" 4
+.IX Item "ev_child_set (ev_child *, int pid, int trace)"
+.PD
+Configures the watcher to wait for status changes of process \f(CW\*(C`pid\*(C'\fR (or
+\&\fIany\fR process if \f(CW\*(C`pid\*(C'\fR is specified as \f(CW0\fR). The callback can look
+at the \f(CW\*(C`rstatus\*(C'\fR member of the \f(CW\*(C`ev_child\*(C'\fR watcher structure to see
+the status word (use the macros from \f(CW\*(C`sys/wait.h\*(C'\fR and see your systems
+\&\f(CW\*(C`waitpid\*(C'\fR documentation). The \f(CW\*(C`rpid\*(C'\fR member contains the pid of the
+process causing the status change. \f(CW\*(C`trace\*(C'\fR must be either \f(CW0\fR (only
+activate the watcher when the process terminates) or \f(CW1\fR (additionally
+activate the watcher when the process is stopped or continued).
+.IP "int pid [read\-only]" 4
+.IX Item "int pid [read-only]"
+The process id this watcher watches out for, or \f(CW0\fR, meaning any process id.
+.IP "int rpid [read\-write]" 4
+.IX Item "int rpid [read-write]"
+The process id that detected a status change.
+.IP "int rstatus [read\-write]" 4
+.IX Item "int rstatus [read-write]"
+The process exit/trace status caused by \f(CW\*(C`rpid\*(C'\fR (see your systems
+\&\f(CW\*(C`waitpid\*(C'\fR and \f(CW\*(C`sys/wait.h\*(C'\fR documentation for details).
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: \f(CW\*(C`fork()\*(C'\fR a new process and install a child handler to wait for
+its completion.
+.PP
+.Vb 1
+\& ev_child cw;
+\&
+\& static void
+\& child_cb (EV_P_ ev_child *w, int revents)
+\& {
+\& ev_child_stop (EV_A_ w);
+\& printf ("process %d exited with status %x\en", w\->rpid, w\->rstatus);
+\& }
+\&
+\& pid_t pid = fork ();
+\&
+\& if (pid < 0)
+\& // error
+\& else if (pid == 0)
+\& {
+\& // the forked child executes here
+\& exit (1);
+\& }
+\& else
+\& {
+\& ev_child_init (&cw, child_cb, pid, 0);
+\& ev_child_start (EV_DEFAULT_ &cw);
+\& }
+.Ve
+.ie n .SS """ev_stat"" \- did the file attributes just change?"
+.el .SS "\f(CWev_stat\fP \- did the file attributes just change?"
+.IX Subsection "ev_stat - did the file attributes just change?"
+This watches a file system path for attribute changes. That is, it calls
+\&\f(CW\*(C`stat\*(C'\fR on that path in regular intervals (or when the \s-1OS\s0 says it changed)
+and sees if it changed compared to the last time, invoking the callback
+if it did. Starting the watcher \f(CW\*(C`stat\*(C'\fR's the file, so only changes that
+happen after the watcher has been started will be reported.
+.PP
+The path does not need to exist: changing from \*(L"path exists\*(R" to \*(L"path does
+not exist\*(R" is a status change like any other. The condition \*(L"path does not
+exist\*(R" (or more correctly \*(L"path cannot be stat'ed\*(R") is signified by the
+\&\f(CW\*(C`st_nlink\*(C'\fR field being zero (which is otherwise always forced to be at
+least one) and all the other fields of the stat buffer having unspecified
+contents.
+.PP
+The path \fImust not\fR end in a slash or contain special components such as
+\&\f(CW\*(C`.\*(C'\fR or \f(CW\*(C`..\*(C'\fR. The path \fIshould\fR be absolute: If it is relative and
+your working directory changes, then the behaviour is undefined.
+.PP
+Since there is no portable change notification interface available, the
+portable implementation simply calls \f(CWstat(2)\fR regularly on the path
+to see if it changed somehow. You can specify a recommended polling
+interval for this case. If you specify a polling interval of \f(CW0\fR (highly
+recommended!) then a \fIsuitable, unspecified default\fR value will be used
+(which you can expect to be around five seconds, although this might
+change dynamically). Libev will also impose a minimum interval which is
+currently around \f(CW0.1\fR, but that's usually overkill.
+.PP
+This watcher type is not meant for massive numbers of stat watchers,
+as even with OS-supported change notifications, this can be
+resource-intensive.
+.PP
+At the time of this writing, the only OS-specific interface implemented
+is the Linux inotify interface (implementing kqueue support is left as an
+exercise for the reader. Note, however, that the author sees no way of
+implementing \f(CW\*(C`ev_stat\*(C'\fR semantics with kqueue, except as a hint).
+.PP
+\fI\s-1ABI\s0 Issues (Largefile Support)\fR
+.IX Subsection "ABI Issues (Largefile Support)"
+.PP
+Libev by default (unless the user overrides this) uses the default
+compilation environment, which means that on systems with large file
+support disabled by default, you get the 32 bit version of the stat
+structure. When using the library from programs that change the \s-1ABI\s0 to
+use 64 bit file offsets the programs will fail. In that case you have to
+compile libev with the same flags to get binary compatibility. This is
+obviously the case with any flags that change the \s-1ABI,\s0 but the problem is
+most noticeably displayed with ev_stat and large file support.
+.PP
+The solution for this is to lobby your distribution maker to make large
+file interfaces available by default (as e.g. FreeBSD does) and not
+optional. Libev cannot simply switch on large file support because it has
+to exchange stat structures with application programs compiled using the
+default compilation environment.
+.PP
+\fIInotify and Kqueue\fR
+.IX Subsection "Inotify and Kqueue"
+.PP
+When \f(CW\*(C`inotify (7)\*(C'\fR support has been compiled into libev and present at
+runtime, it will be used to speed up change detection where possible. The
+inotify descriptor will be created lazily when the first \f(CW\*(C`ev_stat\*(C'\fR
+watcher is being started.
+.PP
+Inotify presence does not change the semantics of \f(CW\*(C`ev_stat\*(C'\fR watchers
+except that changes might be detected earlier, and in some cases, to avoid
+making regular \f(CW\*(C`stat\*(C'\fR calls. Even in the presence of inotify support
+there are many cases where libev has to resort to regular \f(CW\*(C`stat\*(C'\fR polling,
+but as long as kernel 2.6.25 or newer is used (2.6.24 and older have too
+many bugs), the path exists (i.e. stat succeeds), and the path resides on
+a local filesystem (libev currently assumes only ext2/3, jfs, reiserfs and
+xfs are fully working) libev usually gets away without polling.
+.PP
+There is no support for kqueue, as apparently it cannot be used to
+implement this functionality, due to the requirement of having a file
+descriptor open on the object at all times, and detecting renames, unlinks
+etc. is difficult.
+.PP
+\fI\f(CI\*(C`stat ()\*(C'\fI is a synchronous operation\fR
+.IX Subsection "stat () is a synchronous operation"
+.PP
+Libev doesn't normally do any kind of I/O itself, and so is not blocking
+the process. The exception are \f(CW\*(C`ev_stat\*(C'\fR watchers \- those call \f(CW\*(C`stat
+()\*(C'\fR, which is a synchronous operation.
+.PP
+For local paths, this usually doesn't matter: unless the system is very
+busy or the intervals between stat's are large, a stat call will be fast,
+as the path data is usually in memory already (except when starting the
+watcher).
+.PP
+For networked file systems, calling \f(CW\*(C`stat ()\*(C'\fR can block an indefinite
+time due to network issues, and even under good conditions, a stat call
+often takes multiple milliseconds.
+.PP
+Therefore, it is best to avoid using \f(CW\*(C`ev_stat\*(C'\fR watchers on networked
+paths, although this is fully supported by libev.
+.PP
+\fIThe special problem of stat time resolution\fR
+.IX Subsection "The special problem of stat time resolution"
+.PP
+The \f(CW\*(C`stat ()\*(C'\fR system call only supports full-second resolution portably,
+and even on systems where the resolution is higher, most file systems
+still only support whole seconds.
+.PP
+That means that, if the time is the only thing that changes, you can
+easily miss updates: on the first update, \f(CW\*(C`ev_stat\*(C'\fR detects a change and
+calls your callback, which does something. When there is another update
+within the same second, \f(CW\*(C`ev_stat\*(C'\fR will be unable to detect unless the
+stat data does change in other ways (e.g. file size).
+.PP
+The solution to this is to delay acting on a change for slightly more
+than a second (or till slightly after the next full second boundary), using
+a roughly one-second-delay \f(CW\*(C`ev_timer\*(C'\fR (e.g. \f(CW\*(C`ev_timer_set (w, 0., 1.02);
+ev_timer_again (loop, w)\*(C'\fR).
+.PP
+The \f(CW.02\fR offset is added to work around small timing inconsistencies
+of some operating systems (where the second counter of the current time
+might be be delayed. One such system is the Linux kernel, where a call to
+\&\f(CW\*(C`gettimeofday\*(C'\fR might return a timestamp with a full second later than
+a subsequent \f(CW\*(C`time\*(C'\fR call \- if the equivalent of \f(CW\*(C`time ()\*(C'\fR is used to
+update file times then there will be a small window where the kernel uses
+the previous second to update file times but libev might already execute
+the timer callback).
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)" 4
+.IX Item "ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)"
+.PD 0
+.IP "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)" 4
+.IX Item "ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)"
+.PD
+Configures the watcher to wait for status changes of the given
+\&\f(CW\*(C`path\*(C'\fR. The \f(CW\*(C`interval\*(C'\fR is a hint on how quickly a change is expected to
+be detected and should normally be specified as \f(CW0\fR to let libev choose
+a suitable value. The memory pointed to by \f(CW\*(C`path\*(C'\fR must point to the same
+path for as long as the watcher is active.
+.Sp
+The callback will receive an \f(CW\*(C`EV_STAT\*(C'\fR event when a change was detected,
+relative to the attributes at the time the watcher was started (or the
+last change was detected).
+.IP "ev_stat_stat (loop, ev_stat *)" 4
+.IX Item "ev_stat_stat (loop, ev_stat *)"
+Updates the stat buffer immediately with new values. If you change the
+watched path in your callback, you could call this function to avoid
+detecting this change (while introducing a race condition if you are not
+the only one changing the path). Can also be useful simply to find out the
+new values.
+.IP "ev_statdata attr [read\-only]" 4
+.IX Item "ev_statdata attr [read-only]"
+The most-recently detected attributes of the file. Although the type is
+\&\f(CW\*(C`ev_statdata\*(C'\fR, this is usually the (or one of the) \f(CW\*(C`struct stat\*(C'\fR types
+suitable for your system, but you can only rely on the POSIX-standardised
+members to be present. If the \f(CW\*(C`st_nlink\*(C'\fR member is \f(CW0\fR, then there was
+some error while \f(CW\*(C`stat\*(C'\fRing the file.
+.IP "ev_statdata prev [read\-only]" 4
+.IX Item "ev_statdata prev [read-only]"
+The previous attributes of the file. The callback gets invoked whenever
+\&\f(CW\*(C`prev\*(C'\fR != \f(CW\*(C`attr\*(C'\fR, or, more precisely, one or more of these members
+differ: \f(CW\*(C`st_dev\*(C'\fR, \f(CW\*(C`st_ino\*(C'\fR, \f(CW\*(C`st_mode\*(C'\fR, \f(CW\*(C`st_nlink\*(C'\fR, \f(CW\*(C`st_uid\*(C'\fR,
+\&\f(CW\*(C`st_gid\*(C'\fR, \f(CW\*(C`st_rdev\*(C'\fR, \f(CW\*(C`st_size\*(C'\fR, \f(CW\*(C`st_atime\*(C'\fR, \f(CW\*(C`st_mtime\*(C'\fR, \f(CW\*(C`st_ctime\*(C'\fR.
+.IP "ev_tstamp interval [read\-only]" 4
+.IX Item "ev_tstamp interval [read-only]"
+The specified interval.
+.IP "const char *path [read\-only]" 4
+.IX Item "const char *path [read-only]"
+The file system path that is being watched.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Watch \f(CW\*(C`/etc/passwd\*(C'\fR for attribute changes.
+.PP
+.Vb 10
+\& static void
+\& passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
+\& {
+\& /* /etc/passwd changed in some way */
+\& if (w\->attr.st_nlink)
+\& {
+\& printf ("passwd current size %ld\en", (long)w\->attr.st_size);
+\& printf ("passwd current atime %ld\en", (long)w\->attr.st_mtime);
+\& printf ("passwd current mtime %ld\en", (long)w\->attr.st_mtime);
+\& }
+\& else
+\& /* you shalt not abuse printf for puts */
+\& puts ("wow, /etc/passwd is not there, expect problems. "
+\& "if this is windows, they already arrived\en");
+\& }
+\&
+\& ...
+\& ev_stat passwd;
+\&
+\& ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
+\& ev_stat_start (loop, &passwd);
+.Ve
+.PP
+Example: Like above, but additionally use a one-second delay so we do not
+miss updates (however, frequent updates will delay processing, too, so
+one might do the work both on \f(CW\*(C`ev_stat\*(C'\fR callback invocation \fIand\fR on
+\&\f(CW\*(C`ev_timer\*(C'\fR callback invocation).
+.PP
+.Vb 2
+\& static ev_stat passwd;
+\& static ev_timer timer;
+\&
+\& static void
+\& timer_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& ev_timer_stop (EV_A_ w);
+\&
+\& /* now it\*(Aqs one second after the most recent passwd change */
+\& }
+\&
+\& static void
+\& stat_cb (EV_P_ ev_stat *w, int revents)
+\& {
+\& /* reset the one\-second timer */
+\& ev_timer_again (EV_A_ &timer);
+\& }
+\&
+\& ...
+\& ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
+\& ev_stat_start (loop, &passwd);
+\& ev_timer_init (&timer, timer_cb, 0., 1.02);
+.Ve
+.ie n .SS """ev_idle"" \- when you've got nothing better to do..."
+.el .SS "\f(CWev_idle\fP \- when you've got nothing better to do..."
+.IX Subsection "ev_idle - when you've got nothing better to do..."
+Idle watchers trigger events when no other events of the same or higher
+priority are pending (prepare, check and other idle watchers do not count
+as receiving \*(L"events\*(R").
+.PP
+That is, as long as your process is busy handling sockets or timeouts
+(or even signals, imagine) of the same or higher priority it will not be
+triggered. But when your process is idle (or only lower-priority watchers
+are pending), the idle watchers are being called once per event loop
+iteration \- until stopped, that is, or your process receives more events
+and becomes busy again with higher priority stuff.
+.PP
+The most noteworthy effect is that as long as any idle watchers are
+active, the process will not block when waiting for new events.
+.PP
+Apart from keeping your process non-blocking (which is a useful
+effect on its own sometimes), idle watchers are a good place to do
+\&\*(L"pseudo-background processing\*(R", or delay processing stuff to after the
+event loop has handled all outstanding events.
+.PP
+\fIAbusing an \f(CI\*(C`ev_idle\*(C'\fI watcher for its side-effect\fR
+.IX Subsection "Abusing an ev_idle watcher for its side-effect"
+.PP
+As long as there is at least one active idle watcher, libev will never
+sleep unnecessarily. Or in other words, it will loop as fast as possible.
+For this to work, the idle watcher doesn't need to be invoked at all \- the
+lowest priority will do.
+.PP
+This mode of operation can be useful together with an \f(CW\*(C`ev_check\*(C'\fR watcher,
+to do something on each event loop iteration \- for example to balance load
+between different connections.
+.PP
+See \*(L"Abusing an ev_check watcher for its side-effect\*(R" for a longer
+example.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_idle_init (ev_idle *, callback)" 4
+.IX Item "ev_idle_init (ev_idle *, callback)"
+Initialises and configures the idle watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_idle_set\*(C'\fR macro, but using it is utterly pointless,
+believe me.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Dynamically allocate an \f(CW\*(C`ev_idle\*(C'\fR watcher, start it, and in the
+callback, free it. Also, use no error checking, as usual.
+.PP
+.Vb 5
+\& static void
+\& idle_cb (struct ev_loop *loop, ev_idle *w, int revents)
+\& {
+\& // stop the watcher
+\& ev_idle_stop (loop, w);
+\&
+\& // now we can free it
+\& free (w);
+\&
+\& // now do something you wanted to do when the program has
+\& // no longer anything immediate to do.
+\& }
+\&
+\& ev_idle *idle_watcher = malloc (sizeof (ev_idle));
+\& ev_idle_init (idle_watcher, idle_cb);
+\& ev_idle_start (loop, idle_watcher);
+.Ve
+.ie n .SS """ev_prepare"" and ""ev_check"" \- customise your event loop!"
+.el .SS "\f(CWev_prepare\fP and \f(CWev_check\fP \- customise your event loop!"
+.IX Subsection "ev_prepare and ev_check - customise your event loop!"
+Prepare and check watchers are often (but not always) used in pairs:
+prepare watchers get invoked before the process blocks and check watchers
+afterwards.
+.PP
+You \fImust not\fR call \f(CW\*(C`ev_run\*(C'\fR (or similar functions that enter the
+current event loop) or \f(CW\*(C`ev_loop_fork\*(C'\fR from either \f(CW\*(C`ev_prepare\*(C'\fR or
+\&\f(CW\*(C`ev_check\*(C'\fR watchers. Other loops than the current one are fine,
+however. The rationale behind this is that you do not need to check
+for recursion in those watchers, i.e. the sequence will always be
+\&\f(CW\*(C`ev_prepare\*(C'\fR, blocking, \f(CW\*(C`ev_check\*(C'\fR so if you have one watcher of each
+kind they will always be called in pairs bracketing the blocking call.
+.PP
+Their main purpose is to integrate other event mechanisms into libev and
+their use is somewhat advanced. They could be used, for example, to track
+variable changes, implement your own watchers, integrate net-snmp or a
+coroutine library and lots more. They are also occasionally useful if
+you cache some data and want to flush it before blocking (for example,
+in X programs you might want to do an \f(CW\*(C`XFlush ()\*(C'\fR in an \f(CW\*(C`ev_prepare\*(C'\fR
+watcher).
+.PP
+This is done by examining in each prepare call which file descriptors
+need to be watched by the other library, registering \f(CW\*(C`ev_io\*(C'\fR watchers
+for them and starting an \f(CW\*(C`ev_timer\*(C'\fR watcher for any timeouts (many
+libraries provide exactly this functionality). Then, in the check watcher,
+you check for any events that occurred (by checking the pending status
+of all watchers and stopping them) and call back into the library. The
+I/O and timer callbacks will never actually be called (but must be valid
+nevertheless, because you never know, you know?).
+.PP
+As another example, the Perl Coro module uses these hooks to integrate
+coroutines into libev programs, by yielding to other active coroutines
+during each prepare and only letting the process block if no coroutines
+are ready to run (it's actually more complicated: it only runs coroutines
+with priority higher than or equal to the event loop and one coroutine
+of lower priority, but only once, using idle watchers to keep the event
+loop from blocking if lower-priority coroutines are active, thus mapping
+low-priority coroutines to idle/background tasks).
+.PP
+When used for this purpose, it is recommended to give \f(CW\*(C`ev_check\*(C'\fR watchers
+highest (\f(CW\*(C`EV_MAXPRI\*(C'\fR) priority, to ensure that they are being run before
+any other watchers after the poll (this doesn't matter for \f(CW\*(C`ev_prepare\*(C'\fR
+watchers).
+.PP
+Also, \f(CW\*(C`ev_check\*(C'\fR watchers (and \f(CW\*(C`ev_prepare\*(C'\fR watchers, too) should not
+activate (\*(L"feed\*(R") events into libev. While libev fully supports this, they
+might get executed before other \f(CW\*(C`ev_check\*(C'\fR watchers did their job. As
+\&\f(CW\*(C`ev_check\*(C'\fR watchers are often used to embed other (non-libev) event
+loops those other event loops might be in an unusable state until their
+\&\f(CW\*(C`ev_check\*(C'\fR watcher ran (always remind yourself to coexist peacefully with
+others).
+.PP
+\fIAbusing an \f(CI\*(C`ev_check\*(C'\fI watcher for its side-effect\fR
+.IX Subsection "Abusing an ev_check watcher for its side-effect"
+.PP
+\&\f(CW\*(C`ev_check\*(C'\fR (and less often also \f(CW\*(C`ev_prepare\*(C'\fR) watchers can also be
+useful because they are called once per event loop iteration. For
+example, if you want to handle a large number of connections fairly, you
+normally only do a bit of work for each active connection, and if there
+is more work to do, you wait for the next event loop iteration, so other
+connections have a chance of making progress.
+.PP
+Using an \f(CW\*(C`ev_check\*(C'\fR watcher is almost enough: it will be called on the
+next event loop iteration. However, that isn't as soon as possible \-
+without external events, your \f(CW\*(C`ev_check\*(C'\fR watcher will not be invoked.
+.PP
+This is where \f(CW\*(C`ev_idle\*(C'\fR watchers come in handy \- all you need is a
+single global idle watcher that is active as long as you have one active
+\&\f(CW\*(C`ev_check\*(C'\fR watcher. The \f(CW\*(C`ev_idle\*(C'\fR watcher makes sure the event loop
+will not sleep, and the \f(CW\*(C`ev_check\*(C'\fR watcher makes sure a callback gets
+invoked. Neither watcher alone can do that.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_prepare_init (ev_prepare *, callback)" 4
+.IX Item "ev_prepare_init (ev_prepare *, callback)"
+.PD 0
+.IP "ev_check_init (ev_check *, callback)" 4
+.IX Item "ev_check_init (ev_check *, callback)"
+.PD
+Initialises and configures the prepare or check watcher \- they have no
+parameters of any kind. There are \f(CW\*(C`ev_prepare_set\*(C'\fR and \f(CW\*(C`ev_check_set\*(C'\fR
+macros, but using them is utterly, utterly, utterly and completely
+pointless.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+There are a number of principal ways to embed other event loops or modules
+into libev. Here are some ideas on how to include libadns into libev
+(there is a Perl module named \f(CW\*(C`EV::ADNS\*(C'\fR that does this, which you could
+use as a working example. Another Perl module named \f(CW\*(C`EV::Glib\*(C'\fR embeds a
+Glib main context into libev, and finally, \f(CW\*(C`Glib::EV\*(C'\fR embeds \s-1EV\s0 into the
+Glib event loop).
+.PP
+Method 1: Add \s-1IO\s0 watchers and a timeout watcher in a prepare handler,
+and in a check watcher, destroy them and call into libadns. What follows
+is pseudo-code only of course. This requires you to either use a low
+priority for the check watcher or use \f(CW\*(C`ev_clear_pending\*(C'\fR explicitly, as
+the callbacks for the IO/timeout watchers might not have been called yet.
+.PP
+.Vb 2
+\& static ev_io iow [nfd];
+\& static ev_timer tw;
+\&
+\& static void
+\& io_cb (struct ev_loop *loop, ev_io *w, int revents)
+\& {
+\& }
+\&
+\& // create io watchers for each fd and a timer before blocking
+\& static void
+\& adns_prepare_cb (struct ev_loop *loop, ev_prepare *w, int revents)
+\& {
+\& int timeout = 3600000;
+\& struct pollfd fds [nfd];
+\& // actual code will need to loop here and realloc etc.
+\& adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
+\&
+\& /* the callback is illegal, but won\*(Aqt be called as we stop during check */
+\& ev_timer_init (&tw, 0, timeout * 1e\-3, 0.);
+\& ev_timer_start (loop, &tw);
+\&
+\& // create one ev_io per pollfd
+\& for (int i = 0; i < nfd; ++i)
+\& {
+\& ev_io_init (iow + i, io_cb, fds [i].fd,
+\& ((fds [i].events & POLLIN ? EV_READ : 0)
+\& | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
+\&
+\& fds [i].revents = 0;
+\& ev_io_start (loop, iow + i);
+\& }
+\& }
+\&
+\& // stop all watchers after blocking
+\& static void
+\& adns_check_cb (struct ev_loop *loop, ev_check *w, int revents)
+\& {
+\& ev_timer_stop (loop, &tw);
+\&
+\& for (int i = 0; i < nfd; ++i)
+\& {
+\& // set the relevant poll flags
+\& // could also call adns_processreadable etc. here
+\& struct pollfd *fd = fds + i;
+\& int revents = ev_clear_pending (iow + i);
+\& if (revents & EV_READ ) fd\->revents |= fd\->events & POLLIN;
+\& if (revents & EV_WRITE) fd\->revents |= fd\->events & POLLOUT;
+\&
+\& // now stop the watcher
+\& ev_io_stop (loop, iow + i);
+\& }
+\&
+\& adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
+\& }
+.Ve
+.PP
+Method 2: This would be just like method 1, but you run \f(CW\*(C`adns_afterpoll\*(C'\fR
+in the prepare watcher and would dispose of the check watcher.
+.PP
+Method 3: If the module to be embedded supports explicit event
+notification (libadns does), you can also make use of the actual watcher
+callbacks, and only destroy/create the watchers in the prepare watcher.
+.PP
+.Vb 5
+\& static void
+\& timer_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& adns_state ads = (adns_state)w\->data;
+\& update_now (EV_A);
+\&
+\& adns_processtimeouts (ads, &tv_now);
+\& }
+\&
+\& static void
+\& io_cb (EV_P_ ev_io *w, int revents)
+\& {
+\& adns_state ads = (adns_state)w\->data;
+\& update_now (EV_A);
+\&
+\& if (revents & EV_READ ) adns_processreadable (ads, w\->fd, &tv_now);
+\& if (revents & EV_WRITE) adns_processwriteable (ads, w\->fd, &tv_now);
+\& }
+\&
+\& // do not ever call adns_afterpoll
+.Ve
+.PP
+Method 4: Do not use a prepare or check watcher because the module you
+want to embed is not flexible enough to support it. Instead, you can
+override their poll function. The drawback with this solution is that the
+main loop is now no longer controllable by \s-1EV.\s0 The \f(CW\*(C`Glib::EV\*(C'\fR module uses
+this approach, effectively embedding \s-1EV\s0 as a client into the horrible
+libglib event loop.
+.PP
+.Vb 4
+\& static gint
+\& event_poll_func (GPollFD *fds, guint nfds, gint timeout)
+\& {
+\& int got_events = 0;
+\&
+\& for (n = 0; n < nfds; ++n)
+\& // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
+\&
+\& if (timeout >= 0)
+\& // create/start timer
+\&
+\& // poll
+\& ev_run (EV_A_ 0);
+\&
+\& // stop timer again
+\& if (timeout >= 0)
+\& ev_timer_stop (EV_A_ &to);
+\&
+\& // stop io watchers again \- their callbacks should have set
+\& for (n = 0; n < nfds; ++n)
+\& ev_io_stop (EV_A_ iow [n]);
+\&
+\& return got_events;
+\& }
+.Ve
+.ie n .SS """ev_embed"" \- when one backend isn't enough..."
+.el .SS "\f(CWev_embed\fP \- when one backend isn't enough..."
+.IX Subsection "ev_embed - when one backend isn't enough..."
+This is a rather advanced watcher type that lets you embed one event loop
+into another (currently only \f(CW\*(C`ev_io\*(C'\fR events are supported in the embedded
+loop, other types of watchers might be handled in a delayed or incorrect
+fashion and must not be used).
+.PP
+There are primarily two reasons you would want that: work around bugs and
+prioritise I/O.
+.PP
+As an example for a bug workaround, the kqueue backend might only support
+sockets on some platform, so it is unusable as generic backend, but you
+still want to make use of it because you have many sockets and it scales
+so nicely. In this case, you would create a kqueue-based loop and embed
+it into your default loop (which might use e.g. poll). Overall operation
+will be a bit slower because first libev has to call \f(CW\*(C`poll\*(C'\fR and then
+\&\f(CW\*(C`kevent\*(C'\fR, but at least you can use both mechanisms for what they are
+best: \f(CW\*(C`kqueue\*(C'\fR for scalable sockets and \f(CW\*(C`poll\*(C'\fR if you want it to work :)
+.PP
+As for prioritising I/O: under rare circumstances you have the case where
+some fds have to be watched and handled very quickly (with low latency),
+and even priorities and idle watchers might have too much overhead. In
+this case you would put all the high priority stuff in one loop and all
+the rest in a second one, and embed the second one in the first.
+.PP
+As long as the watcher is active, the callback will be invoked every
+time there might be events pending in the embedded loop. The callback
+must then call \f(CW\*(C`ev_embed_sweep (mainloop, watcher)\*(C'\fR to make a single
+sweep and invoke their callbacks (the callback doesn't need to invoke the
+\&\f(CW\*(C`ev_embed_sweep\*(C'\fR function directly, it could also start an idle watcher
+to give the embedded loop strictly lower priority for example).
+.PP
+You can also set the callback to \f(CW0\fR, in which case the embed watcher
+will automatically execute the embedded loop sweep whenever necessary.
+.PP
+Fork detection will be handled transparently while the \f(CW\*(C`ev_embed\*(C'\fR watcher
+is active, i.e., the embedded loop will automatically be forked when the
+embedding loop forks. In other cases, the user is responsible for calling
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR on the embedded loop.
+.PP
+Unfortunately, not all backends are embeddable: only the ones returned by
+\&\f(CW\*(C`ev_embeddable_backends\*(C'\fR are, which, unfortunately, does not include any
+portable one.
+.PP
+So when you want to use this feature you will always have to be prepared
+that you cannot get an embeddable loop. The recommended way to get around
+this is to have a separate variables for your embeddable loop, try to
+create it, and if that fails, use the normal loop for everything.
+.PP
+\fI\f(CI\*(C`ev_embed\*(C'\fI and fork\fR
+.IX Subsection "ev_embed and fork"
+.PP
+While the \f(CW\*(C`ev_embed\*(C'\fR watcher is running, forks in the embedding loop will
+automatically be applied to the embedded loop as well, so no special
+fork handling is required in that case. When the watcher is not running,
+however, it is still the task of the libev user to call \f(CW\*(C`ev_loop_fork ()\*(C'\fR
+as applicable.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)" 4
+.IX Item "ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)"
+.PD 0
+.IP "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)" 4
+.IX Item "ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)"
+.PD
+Configures the watcher to embed the given loop, which must be
+embeddable. If the callback is \f(CW0\fR, then \f(CW\*(C`ev_embed_sweep\*(C'\fR will be
+invoked automatically, otherwise it is the responsibility of the callback
+to invoke it (it will continue to be called until the sweep has been done,
+if you do not want that, you need to temporarily stop the embed watcher).
+.IP "ev_embed_sweep (loop, ev_embed *)" 4
+.IX Item "ev_embed_sweep (loop, ev_embed *)"
+Make a single, non-blocking sweep over the embedded loop. This works
+similarly to \f(CW\*(C`ev_run (embedded_loop, EVRUN_NOWAIT)\*(C'\fR, but in the most
+appropriate way for embedded loops.
+.IP "struct ev_loop *other [read\-only]" 4
+.IX Item "struct ev_loop *other [read-only]"
+The embedded event loop.
+.PP
+\fIExamples\fR
+.IX Subsection "Examples"
+.PP
+Example: Try to get an embeddable event loop and embed it into the default
+event loop. If that is not possible, use the default loop. The default
+loop is stored in \f(CW\*(C`loop_hi\*(C'\fR, while the embeddable loop is stored in
+\&\f(CW\*(C`loop_lo\*(C'\fR (which is \f(CW\*(C`loop_hi\*(C'\fR in the case no embeddable loop can be
+used).
+.PP
+.Vb 3
+\& struct ev_loop *loop_hi = ev_default_init (0);
+\& struct ev_loop *loop_lo = 0;
+\& ev_embed embed;
+\&
+\& // see if there is a chance of getting one that works
+\& // (remember that a flags value of 0 means autodetection)
+\& loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
+\& ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
+\& : 0;
+\&
+\& // if we got one, then embed it, otherwise default to loop_hi
+\& if (loop_lo)
+\& {
+\& ev_embed_init (&embed, 0, loop_lo);
+\& ev_embed_start (loop_hi, &embed);
+\& }
+\& else
+\& loop_lo = loop_hi;
+.Ve
+.PP
+Example: Check if kqueue is available but not recommended and create
+a kqueue backend for use with sockets (which usually work with any
+kqueue implementation). Store the kqueue/socket\-only event loop in
+\&\f(CW\*(C`loop_socket\*(C'\fR. (One might optionally use \f(CW\*(C`EVFLAG_NOENV\*(C'\fR, too).
+.PP
+.Vb 3
+\& struct ev_loop *loop = ev_default_init (0);
+\& struct ev_loop *loop_socket = 0;
+\& ev_embed embed;
+\&
+\& if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
+\& if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
+\& {
+\& ev_embed_init (&embed, 0, loop_socket);
+\& ev_embed_start (loop, &embed);
+\& }
+\&
+\& if (!loop_socket)
+\& loop_socket = loop;
+\&
+\& // now use loop_socket for all sockets, and loop for everything else
+.Ve
+.ie n .SS """ev_fork"" \- the audacity to resume the event loop after a fork"
+.el .SS "\f(CWev_fork\fP \- the audacity to resume the event loop after a fork"
+.IX Subsection "ev_fork - the audacity to resume the event loop after a fork"
+Fork watchers are called when a \f(CW\*(C`fork ()\*(C'\fR was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR). The invocation is done before the event loop blocks next
+and before \f(CW\*(C`ev_check\*(C'\fR watchers are being called, and only in the child
+after the fork. If whoever good citizen calling \f(CW\*(C`ev_default_fork\*(C'\fR cheats
+and calls it in the wrong process, the fork handlers will be invoked, too,
+of course.
+.PP
+\fIThe special problem of life after fork \- how is it possible?\fR
+.IX Subsection "The special problem of life after fork - how is it possible?"
+.PP
+Most uses of \f(CW\*(C`fork ()\*(C'\fR consist of forking, then some simple calls to set
+up/change the process environment, followed by a call to \f(CW\*(C`exec()\*(C'\fR. This
+sequence should be handled by libev without any problems.
+.PP
+This changes when the application actually wants to do event handling
+in the child, or both parent in child, in effect \*(L"continuing\*(R" after the
+fork.
+.PP
+The default mode of operation (for libev, with application help to detect
+forks) is to duplicate all the state in the child, as would be expected
+when \fIeither\fR the parent \fIor\fR the child process continues.
+.PP
+When both processes want to continue using libev, then this is usually the
+wrong result. In that case, usually one process (typically the parent) is
+supposed to continue with all watchers in place as before, while the other
+process typically wants to start fresh, i.e. without any active watchers.
+.PP
+The cleanest and most efficient way to achieve that with libev is to
+simply create a new event loop, which of course will be \*(L"empty\*(R", and
+use that for new watchers. This has the advantage of not touching more
+memory than necessary, and thus avoiding the copy-on-write, and the
+disadvantage of having to use multiple event loops (which do not support
+signal watchers).
+.PP
+When this is not possible, or you want to use the default loop for
+other reasons, then in the process that wants to start \*(L"fresh\*(R", call
+\&\f(CW\*(C`ev_loop_destroy (EV_DEFAULT)\*(C'\fR followed by \f(CW\*(C`ev_default_loop (...)\*(C'\fR.
+Destroying the default loop will \*(L"orphan\*(R" (not stop) all registered
+watchers, so you have to be careful not to execute code that modifies
+those watchers. Note also that in that case, you have to re-register any
+signal watchers.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_fork_init (ev_fork *, callback)" 4
+.IX Item "ev_fork_init (ev_fork *, callback)"
+Initialises and configures the fork watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_fork_set\*(C'\fR macro, but using it is utterly pointless,
+really.
+.ie n .SS """ev_cleanup"" \- even the best things end"
+.el .SS "\f(CWev_cleanup\fP \- even the best things end"
+.IX Subsection "ev_cleanup - even the best things end"
+Cleanup watchers are called just before the event loop is being destroyed
+by a call to \f(CW\*(C`ev_loop_destroy\*(C'\fR.
+.PP
+While there is no guarantee that the event loop gets destroyed, cleanup
+watchers provide a convenient method to install cleanup hooks for your
+program, worker threads and so on \- you just to make sure to destroy the
+loop when you want them to be invoked.
+.PP
+Cleanup watchers are invoked in the same way as any other watcher. Unlike
+all other watchers, they do not keep a reference to the event loop (which
+makes a lot of sense if you think about it). Like all other watchers, you
+can call libev functions in the callback, except \f(CW\*(C`ev_cleanup_start\*(C'\fR.
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_cleanup_init (ev_cleanup *, callback)" 4
+.IX Item "ev_cleanup_init (ev_cleanup *, callback)"
+Initialises and configures the cleanup watcher \- it has no parameters of
+any kind. There is a \f(CW\*(C`ev_cleanup_set\*(C'\fR macro, but using it is utterly
+pointless, I assure you.
+.PP
+Example: Register an atexit handler to destroy the default loop, so any
+cleanup functions are called.
+.PP
+.Vb 5
+\& static void
+\& program_exits (void)
+\& {
+\& ev_loop_destroy (EV_DEFAULT_UC);
+\& }
+\&
+\& ...
+\& atexit (program_exits);
+.Ve
+.ie n .SS """ev_async"" \- how to wake up an event loop"
+.el .SS "\f(CWev_async\fP \- how to wake up an event loop"
+.IX Subsection "ev_async - how to wake up an event loop"
+In general, you cannot use an \f(CW\*(C`ev_loop\*(C'\fR from multiple threads or other
+asynchronous sources such as signal handlers (as opposed to multiple event
+loops \- those are of course safe to use in different threads).
+.PP
+Sometimes, however, you need to wake up an event loop you do not control,
+for example because it belongs to another thread. This is what \f(CW\*(C`ev_async\*(C'\fR
+watchers do: as long as the \f(CW\*(C`ev_async\*(C'\fR watcher is active, you can signal
+it by calling \f(CW\*(C`ev_async_send\*(C'\fR, which is thread\- and signal safe.
+.PP
+This functionality is very similar to \f(CW\*(C`ev_signal\*(C'\fR watchers, as signals,
+too, are asynchronous in nature, and signals, too, will be compressed
+(i.e. the number of callback invocations may be less than the number of
+\&\f(CW\*(C`ev_async_send\*(C'\fR calls). In fact, you could use signal watchers as a kind
+of \*(L"global async watchers\*(R" by using a watcher on an otherwise unused
+signal, and \f(CW\*(C`ev_feed_signal\*(C'\fR to signal this watcher from another thread,
+even without knowing which loop owns the signal.
+.PP
+\fIQueueing\fR
+.IX Subsection "Queueing"
+.PP
+\&\f(CW\*(C`ev_async\*(C'\fR does not support queueing of data in any way. The reason
+is that the author does not know of a simple (or any) algorithm for a
+multiple-writer-single-reader queue that works in all cases and doesn't
+need elaborate support such as pthreads or unportable memory access
+semantics.
+.PP
+That means that if you want to queue data, you have to provide your own
+queue. But at least I can tell you how to implement locking around your
+queue:
+.IP "queueing from a signal handler context" 4
+.IX Item "queueing from a signal handler context"
+To implement race-free queueing, you simply add to the queue in the signal
+handler but you block the signal handler in the watcher callback. Here is
+an example that does that for some fictitious \s-1SIGUSR1\s0 handler:
+.Sp
+.Vb 1
+\& static ev_async mysig;
+\&
+\& static void
+\& sigusr1_handler (void)
+\& {
+\& sometype data;
+\&
+\& // no locking etc.
+\& queue_put (data);
+\& ev_async_send (EV_DEFAULT_ &mysig);
+\& }
+\&
+\& static void
+\& mysig_cb (EV_P_ ev_async *w, int revents)
+\& {
+\& sometype data;
+\& sigset_t block, prev;
+\&
+\& sigemptyset (&block);
+\& sigaddset (&block, SIGUSR1);
+\& sigprocmask (SIG_BLOCK, &block, &prev);
+\&
+\& while (queue_get (&data))
+\& process (data);
+\&
+\& if (sigismember (&prev, SIGUSR1)
+\& sigprocmask (SIG_UNBLOCK, &block, 0);
+\& }
+.Ve
+.Sp
+(Note: pthreads in theory requires you to use \f(CW\*(C`pthread_setmask\*(C'\fR
+instead of \f(CW\*(C`sigprocmask\*(C'\fR when you use threads, but libev doesn't do it
+either...).
+.IP "queueing from a thread context" 4
+.IX Item "queueing from a thread context"
+The strategy for threads is different, as you cannot (easily) block
+threads but you can easily preempt them, so to queue safely you need to
+employ a traditional mutex lock, such as in this pthread example:
+.Sp
+.Vb 2
+\& static ev_async mysig;
+\& static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER;
+\&
+\& static void
+\& otherthread (void)
+\& {
+\& // only need to lock the actual queueing operation
+\& pthread_mutex_lock (&mymutex);
+\& queue_put (data);
+\& pthread_mutex_unlock (&mymutex);
+\&
+\& ev_async_send (EV_DEFAULT_ &mysig);
+\& }
+\&
+\& static void
+\& mysig_cb (EV_P_ ev_async *w, int revents)
+\& {
+\& pthread_mutex_lock (&mymutex);
+\&
+\& while (queue_get (&data))
+\& process (data);
+\&
+\& pthread_mutex_unlock (&mymutex);
+\& }
+.Ve
+.PP
+\fIWatcher-Specific Functions and Data Members\fR
+.IX Subsection "Watcher-Specific Functions and Data Members"
+.IP "ev_async_init (ev_async *, callback)" 4
+.IX Item "ev_async_init (ev_async *, callback)"
+Initialises and configures the async watcher \- it has no parameters of any
+kind. There is a \f(CW\*(C`ev_async_set\*(C'\fR macro, but using it is utterly pointless,
+trust me.
+.IP "ev_async_send (loop, ev_async *)" 4
+.IX Item "ev_async_send (loop, ev_async *)"
+Sends/signals/activates the given \f(CW\*(C`ev_async\*(C'\fR watcher, that is, feeds
+an \f(CW\*(C`EV_ASYNC\*(C'\fR event on the watcher into the event loop, and instantly
+returns.
+.Sp
+Unlike \f(CW\*(C`ev_feed_event\*(C'\fR, this call is safe to do from other threads,
+signal or similar contexts (see the discussion of \f(CW\*(C`EV_ATOMIC_T\*(C'\fR in the
+embedding section below on what exactly this means).
+.Sp
+Note that, as with other watchers in libev, multiple events might get
+compressed into a single callback invocation (another way to look at
+this is that \f(CW\*(C`ev_async\*(C'\fR watchers are level-triggered: they are set on
+\&\f(CW\*(C`ev_async_send\*(C'\fR, reset when the event loop detects that).
+.Sp
+This call incurs the overhead of at most one extra system call per event
+loop iteration, if the event loop is blocked, and no syscall at all if
+the event loop (or your program) is processing events. That means that
+repeated calls are basically free (there is no need to avoid calls for
+performance reasons) and that the overhead becomes smaller (typically
+zero) under load.
+.IP "bool = ev_async_pending (ev_async *)" 4
+.IX Item "bool = ev_async_pending (ev_async *)"
+Returns a non-zero value when \f(CW\*(C`ev_async_send\*(C'\fR has been called on the
+watcher but the event has not yet been processed (or even noted) by the
+event loop.
+.Sp
+\&\f(CW\*(C`ev_async_send\*(C'\fR sets a flag in the watcher and wakes up the loop. When
+the loop iterates next and checks for the watcher to have become active,
+it will reset the flag again. \f(CW\*(C`ev_async_pending\*(C'\fR can be used to very
+quickly check whether invoking the loop might be a good idea.
+.Sp
+Not that this does \fInot\fR check whether the watcher itself is pending,
+only whether it has been requested to make this watcher pending: there
+is a time window between the event loop checking and resetting the async
+notification, and the callback being invoked.
+.SH "OTHER FUNCTIONS"
+.IX Header "OTHER FUNCTIONS"
+There are some other functions of possible interest. Described. Here. Now.
+.IP "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)" 4
+.IX Item "ev_once (loop, int fd, int events, ev_tstamp timeout, callback)"
+This function combines a simple timer and an I/O watcher, calls your
+callback on whichever event happens first and automatically stops both
+watchers. This is useful if you want to wait for a single event on an fd
+or timeout without having to allocate/configure/start/stop/free one or
+more watchers yourself.
+.Sp
+If \f(CW\*(C`fd\*(C'\fR is less than 0, then no I/O watcher will be started and the
+\&\f(CW\*(C`events\*(C'\fR argument is being ignored. Otherwise, an \f(CW\*(C`ev_io\*(C'\fR watcher for
+the given \f(CW\*(C`fd\*(C'\fR and \f(CW\*(C`events\*(C'\fR set will be created and started.
+.Sp
+If \f(CW\*(C`timeout\*(C'\fR is less than 0, then no timeout watcher will be
+started. Otherwise an \f(CW\*(C`ev_timer\*(C'\fR watcher with after = \f(CW\*(C`timeout\*(C'\fR (and
+repeat = 0) will be started. \f(CW0\fR is a valid timeout.
+.Sp
+The callback has the type \f(CW\*(C`void (*cb)(int revents, void *arg)\*(C'\fR and is
+passed an \f(CW\*(C`revents\*(C'\fR set like normal event callbacks (a combination of
+\&\f(CW\*(C`EV_ERROR\*(C'\fR, \f(CW\*(C`EV_READ\*(C'\fR, \f(CW\*(C`EV_WRITE\*(C'\fR or \f(CW\*(C`EV_TIMER\*(C'\fR) and the \f(CW\*(C`arg\*(C'\fR
+value passed to \f(CW\*(C`ev_once\*(C'\fR. Note that it is possible to receive \fIboth\fR
+a timeout and an io event at the same time \- you probably should give io
+events precedence.
+.Sp
+Example: wait up to ten seconds for data to appear on \s-1STDIN_FILENO.\s0
+.Sp
+.Vb 7
+\& static void stdin_ready (int revents, void *arg)
+\& {
+\& if (revents & EV_READ)
+\& /* stdin might have data for us, joy! */;
+\& else if (revents & EV_TIMER)
+\& /* doh, nothing entered */;
+\& }
+\&
+\& ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
+.Ve
+.IP "ev_feed_fd_event (loop, int fd, int revents)" 4
+.IX Item "ev_feed_fd_event (loop, int fd, int revents)"
+Feed an event on the given fd, as if a file descriptor backend detected
+the given events.
+.IP "ev_feed_signal_event (loop, int signum)" 4
+.IX Item "ev_feed_signal_event (loop, int signum)"
+Feed an event as if the given signal occurred. See also \f(CW\*(C`ev_feed_signal\*(C'\fR,
+which is async-safe.
+.SH "COMMON OR USEFUL IDIOMS (OR BOTH)"
+.IX Header "COMMON OR USEFUL IDIOMS (OR BOTH)"
+This section explains some common idioms that are not immediately
+obvious. Note that examples are sprinkled over the whole manual, and this
+section only contains stuff that wouldn't fit anywhere else.
+.SS "\s-1ASSOCIATING CUSTOM DATA WITH A WATCHER\s0"
+.IX Subsection "ASSOCIATING CUSTOM DATA WITH A WATCHER"
+Each watcher has, by default, a \f(CW\*(C`void *data\*(C'\fR member that you can read
+or modify at any time: libev will completely ignore it. This can be used
+to associate arbitrary data with your watcher. If you need more data and
+don't want to allocate memory separately and store a pointer to it in that
+data member, you can also \*(L"subclass\*(R" the watcher type and provide your own
+data:
+.PP
+.Vb 7
+\& struct my_io
+\& {
+\& ev_io io;
+\& int otherfd;
+\& void *somedata;
+\& struct whatever *mostinteresting;
+\& };
+\&
+\& ...
+\& struct my_io w;
+\& ev_io_init (&w.io, my_cb, fd, EV_READ);
+.Ve
+.PP
+And since your callback will be called with a pointer to the watcher, you
+can cast it back to your own type:
+.PP
+.Vb 5
+\& static void my_cb (struct ev_loop *loop, ev_io *w_, int revents)
+\& {
+\& struct my_io *w = (struct my_io *)w_;
+\& ...
+\& }
+.Ve
+.PP
+More interesting and less C\-conformant ways of casting your callback
+function type instead have been omitted.
+.SS "\s-1BUILDING YOUR OWN COMPOSITE WATCHERS\s0"
+.IX Subsection "BUILDING YOUR OWN COMPOSITE WATCHERS"
+Another common scenario is to use some data structure with multiple
+embedded watchers, in effect creating your own watcher that combines
+multiple libev event sources into one \*(L"super-watcher\*(R":
+.PP
+.Vb 6
+\& struct my_biggy
+\& {
+\& int some_data;
+\& ev_timer t1;
+\& ev_timer t2;
+\& }
+.Ve
+.PP
+In this case getting the pointer to \f(CW\*(C`my_biggy\*(C'\fR is a bit more
+complicated: Either you store the address of your \f(CW\*(C`my_biggy\*(C'\fR struct in
+the \f(CW\*(C`data\*(C'\fR member of the watcher (for woozies or \*(C+ coders), or you need
+to use some pointer arithmetic using \f(CW\*(C`offsetof\*(C'\fR inside your watchers (for
+real programmers):
+.PP
+.Vb 1
+\& #include <stddef.h>
+\&
+\& static void
+\& t1_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& struct my_biggy big = (struct my_biggy *)
+\& (((char *)w) \- offsetof (struct my_biggy, t1));
+\& }
+\&
+\& static void
+\& t2_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& struct my_biggy big = (struct my_biggy *)
+\& (((char *)w) \- offsetof (struct my_biggy, t2));
+\& }
+.Ve
+.SS "\s-1AVOIDING FINISHING BEFORE RETURNING\s0"
+.IX Subsection "AVOIDING FINISHING BEFORE RETURNING"
+Often you have structures like this in event-based programs:
+.PP
+.Vb 4
+\& callback ()
+\& {
+\& free (request);
+\& }
+\&
+\& request = start_new_request (..., callback);
+.Ve
+.PP
+The intent is to start some \*(L"lengthy\*(R" operation. The \f(CW\*(C`request\*(C'\fR could be
+used to cancel the operation, or do other things with it.
+.PP
+It's not uncommon to have code paths in \f(CW\*(C`start_new_request\*(C'\fR that
+immediately invoke the callback, for example, to report errors. Or you add
+some caching layer that finds that it can skip the lengthy aspects of the
+operation and simply invoke the callback with the result.
+.PP
+The problem here is that this will happen \fIbefore\fR \f(CW\*(C`start_new_request\*(C'\fR
+has returned, so \f(CW\*(C`request\*(C'\fR is not set.
+.PP
+Even if you pass the request by some safer means to the callback, you
+might want to do something to the request after starting it, such as
+canceling it, which probably isn't working so well when the callback has
+already been invoked.
+.PP
+A common way around all these issues is to make sure that
+\&\f(CW\*(C`start_new_request\*(C'\fR \fIalways\fR returns before the callback is invoked. If
+\&\f(CW\*(C`start_new_request\*(C'\fR immediately knows the result, it can artificially
+delay invoking the callback by using a \f(CW\*(C`prepare\*(C'\fR or \f(CW\*(C`idle\*(C'\fR watcher for
+example, or more sneakily, by reusing an existing (stopped) watcher and
+pushing it into the pending queue:
+.PP
+.Vb 2
+\& ev_set_cb (watcher, callback);
+\& ev_feed_event (EV_A_ watcher, 0);
+.Ve
+.PP
+This way, \f(CW\*(C`start_new_request\*(C'\fR can safely return before the callback is
+invoked, while not delaying callback invocation too much.
+.SS "\s-1MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS\s0"
+.IX Subsection "MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS"
+Often (especially in \s-1GUI\s0 toolkits) there are places where you have
+\&\fImodal\fR interaction, which is most easily implemented by recursively
+invoking \f(CW\*(C`ev_run\*(C'\fR.
+.PP
+This brings the problem of exiting \- a callback might want to finish the
+main \f(CW\*(C`ev_run\*(C'\fR call, but not the nested one (e.g. user clicked \*(L"Quit\*(R", but
+a modal \*(L"Are you sure?\*(R" dialog is still waiting), or just the nested one
+and not the main one (e.g. user clocked \*(L"Ok\*(R" in a modal dialog), or some
+other combination: In these cases, a simple \f(CW\*(C`ev_break\*(C'\fR will not work.
+.PP
+The solution is to maintain \*(L"break this loop\*(R" variable for each \f(CW\*(C`ev_run\*(C'\fR
+invocation, and use a loop around \f(CW\*(C`ev_run\*(C'\fR until the condition is
+triggered, using \f(CW\*(C`EVRUN_ONCE\*(C'\fR:
+.PP
+.Vb 2
+\& // main loop
+\& int exit_main_loop = 0;
+\&
+\& while (!exit_main_loop)
+\& ev_run (EV_DEFAULT_ EVRUN_ONCE);
+\&
+\& // in a modal watcher
+\& int exit_nested_loop = 0;
+\&
+\& while (!exit_nested_loop)
+\& ev_run (EV_A_ EVRUN_ONCE);
+.Ve
+.PP
+To exit from any of these loops, just set the corresponding exit variable:
+.PP
+.Vb 2
+\& // exit modal loop
+\& exit_nested_loop = 1;
+\&
+\& // exit main program, after modal loop is finished
+\& exit_main_loop = 1;
+\&
+\& // exit both
+\& exit_main_loop = exit_nested_loop = 1;
+.Ve
+.SS "\s-1THREAD LOCKING EXAMPLE\s0"
+.IX Subsection "THREAD LOCKING EXAMPLE"
+Here is a fictitious example of how to run an event loop in a different
+thread from where callbacks are being invoked and watchers are
+created/added/removed.
+.PP
+For a real-world example, see the \f(CW\*(C`EV::Loop::Async\*(C'\fR perl module,
+which uses exactly this technique (which is suited for many high-level
+languages).
+.PP
+The example uses a pthread mutex to protect the loop data, a condition
+variable to wait for callback invocations, an async watcher to notify the
+event loop thread and an unspecified mechanism to wake up the main thread.
+.PP
+First, you need to associate some data with the event loop:
+.PP
+.Vb 6
+\& typedef struct {
+\& mutex_t lock; /* global loop lock */
+\& ev_async async_w;
+\& thread_t tid;
+\& cond_t invoke_cv;
+\& } userdata;
+\&
+\& void prepare_loop (EV_P)
+\& {
+\& // for simplicity, we use a static userdata struct.
+\& static userdata u;
+\&
+\& ev_async_init (&u\->async_w, async_cb);
+\& ev_async_start (EV_A_ &u\->async_w);
+\&
+\& pthread_mutex_init (&u\->lock, 0);
+\& pthread_cond_init (&u\->invoke_cv, 0);
+\&
+\& // now associate this with the loop
+\& ev_set_userdata (EV_A_ u);
+\& ev_set_invoke_pending_cb (EV_A_ l_invoke);
+\& ev_set_loop_release_cb (EV_A_ l_release, l_acquire);
+\&
+\& // then create the thread running ev_run
+\& pthread_create (&u\->tid, 0, l_run, EV_A);
+\& }
+.Ve
+.PP
+The callback for the \f(CW\*(C`ev_async\*(C'\fR watcher does nothing: the watcher is used
+solely to wake up the event loop so it takes notice of any new watchers
+that might have been added:
+.PP
+.Vb 5
+\& static void
+\& async_cb (EV_P_ ev_async *w, int revents)
+\& {
+\& // just used for the side effects
+\& }
+.Ve
+.PP
+The \f(CW\*(C`l_release\*(C'\fR and \f(CW\*(C`l_acquire\*(C'\fR callbacks simply unlock/lock the mutex
+protecting the loop data, respectively.
+.PP
+.Vb 6
+\& static void
+\& l_release (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\& pthread_mutex_unlock (&u\->lock);
+\& }
+\&
+\& static void
+\& l_acquire (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\& pthread_mutex_lock (&u\->lock);
+\& }
+.Ve
+.PP
+The event loop thread first acquires the mutex, and then jumps straight
+into \f(CW\*(C`ev_run\*(C'\fR:
+.PP
+.Vb 4
+\& void *
+\& l_run (void *thr_arg)
+\& {
+\& struct ev_loop *loop = (struct ev_loop *)thr_arg;
+\&
+\& l_acquire (EV_A);
+\& pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
+\& ev_run (EV_A_ 0);
+\& l_release (EV_A);
+\&
+\& return 0;
+\& }
+.Ve
+.PP
+Instead of invoking all pending watchers, the \f(CW\*(C`l_invoke\*(C'\fR callback will
+signal the main thread via some unspecified mechanism (signals? pipe
+writes? \f(CW\*(C`Async::Interrupt\*(C'\fR?) and then waits until all pending watchers
+have been called (in a while loop because a) spurious wakeups are possible
+and b) skipping inter-thread-communication when there are no pending
+watchers is very beneficial):
+.PP
+.Vb 4
+\& static void
+\& l_invoke (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\&
+\& while (ev_pending_count (EV_A))
+\& {
+\& wake_up_other_thread_in_some_magic_or_not_so_magic_way ();
+\& pthread_cond_wait (&u\->invoke_cv, &u\->lock);
+\& }
+\& }
+.Ve
+.PP
+Now, whenever the main thread gets told to invoke pending watchers, it
+will grab the lock, call \f(CW\*(C`ev_invoke_pending\*(C'\fR and then signal the loop
+thread to continue:
+.PP
+.Vb 4
+\& static void
+\& real_invoke_pending (EV_P)
+\& {
+\& userdata *u = ev_userdata (EV_A);
+\&
+\& pthread_mutex_lock (&u\->lock);
+\& ev_invoke_pending (EV_A);
+\& pthread_cond_signal (&u\->invoke_cv);
+\& pthread_mutex_unlock (&u\->lock);
+\& }
+.Ve
+.PP
+Whenever you want to start/stop a watcher or do other modifications to an
+event loop, you will now have to lock:
+.PP
+.Vb 2
+\& ev_timer timeout_watcher;
+\& userdata *u = ev_userdata (EV_A);
+\&
+\& ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+\&
+\& pthread_mutex_lock (&u\->lock);
+\& ev_timer_start (EV_A_ &timeout_watcher);
+\& ev_async_send (EV_A_ &u\->async_w);
+\& pthread_mutex_unlock (&u\->lock);
+.Ve
+.PP
+Note that sending the \f(CW\*(C`ev_async\*(C'\fR watcher is required because otherwise
+an event loop currently blocking in the kernel will have no knowledge
+about the newly added timer. By waking up the loop it will pick up any new
+watchers in the next event loop iteration.
+.SS "\s-1THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS\s0"
+.IX Subsection "THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS"
+While the overhead of a callback that e.g. schedules a thread is small, it
+is still an overhead. If you embed libev, and your main usage is with some
+kind of threads or coroutines, you might want to customise libev so that
+doesn't need callbacks anymore.
+.PP
+Imagine you have coroutines that you can switch to using a function
+\&\f(CW\*(C`switch_to (coro)\*(C'\fR, that libev runs in a coroutine called \f(CW\*(C`libev_coro\*(C'\fR
+and that due to some magic, the currently active coroutine is stored in a
+global called \f(CW\*(C`current_coro\*(C'\fR. Then you can build your own \*(L"wait for libev
+event\*(R" primitive by changing \f(CW\*(C`EV_CB_DECLARE\*(C'\fR and \f(CW\*(C`EV_CB_INVOKE\*(C'\fR (note
+the differing \f(CW\*(C`;\*(C'\fR conventions):
+.PP
+.Vb 2
+\& #define EV_CB_DECLARE(type) struct my_coro *cb;
+\& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb)
+.Ve
+.PP
+That means instead of having a C callback function, you store the
+coroutine to switch to in each watcher, and instead of having libev call
+your callback, you instead have it switch to that coroutine.
+.PP
+A coroutine might now wait for an event with a function called
+\&\f(CW\*(C`wait_for_event\*(C'\fR. (the watcher needs to be started, as always, but it doesn't
+matter when, or whether the watcher is active or not when this function is
+called):
+.PP
+.Vb 6
+\& void
+\& wait_for_event (ev_watcher *w)
+\& {
+\& ev_set_cb (w, current_coro);
+\& switch_to (libev_coro);
+\& }
+.Ve
+.PP
+That basically suspends the coroutine inside \f(CW\*(C`wait_for_event\*(C'\fR and
+continues the libev coroutine, which, when appropriate, switches back to
+this or any other coroutine.
+.PP
+You can do similar tricks if you have, say, threads with an event queue \-
+instead of storing a coroutine, you store the queue object and instead of
+switching to a coroutine, you push the watcher onto the queue and notify
+any waiters.
+.PP
+To embed libev, see \*(L"\s-1EMBEDDING\*(R"\s0, but in short, it's easiest to create two
+files, \fImy_ev.h\fR and \fImy_ev.c\fR that include the respective libev files:
+.PP
+.Vb 4
+\& // my_ev.h
+\& #define EV_CB_DECLARE(type) struct my_coro *cb;
+\& #define EV_CB_INVOKE(watcher) switch_to ((watcher)\->cb)
+\& #include "../libev/ev.h"
+\&
+\& // my_ev.c
+\& #define EV_H "my_ev.h"
+\& #include "../libev/ev.c"
+.Ve
+.PP
+And then use \fImy_ev.h\fR when you would normally use \fIev.h\fR, and compile
+\&\fImy_ev.c\fR into your project. When properly specifying include paths, you
+can even use \fIev.h\fR as header file name directly.
+.SH "LIBEVENT EMULATION"
+.IX Header "LIBEVENT EMULATION"
+Libev offers a compatibility emulation layer for libevent. It cannot
+emulate the internals of libevent, so here are some usage hints:
+.IP "\(bu" 4
+Only the libevent\-1.4.1\-beta \s-1API\s0 is being emulated.
+.Sp
+This was the newest libevent version available when libev was implemented,
+and is still mostly unchanged in 2010.
+.IP "\(bu" 4
+Use it by including <event.h>, as usual.
+.IP "\(bu" 4
+The following members are fully supported: ev_base, ev_callback,
+ev_arg, ev_fd, ev_res, ev_events.
+.IP "\(bu" 4
+Avoid using ev_flags and the EVLIST_*\-macros, while it is
+maintained by libev, it does not work exactly the same way as in libevent (consider
+it a private \s-1API\s0).
+.IP "\(bu" 4
+Priorities are not currently supported. Initialising priorities
+will fail and all watchers will have the same priority, even though there
+is an ev_pri field.
+.IP "\(bu" 4
+In libevent, the last base created gets the signals, in libev, the
+base that registered the signal gets the signals.
+.IP "\(bu" 4
+Other members are not supported.
+.IP "\(bu" 4
+The libev emulation is \fInot\fR \s-1ABI\s0 compatible to libevent, you need
+to use the libev header file and library.
+.SH "\*(C+ SUPPORT"
+.IX Header " SUPPORT"
+.SS "C \s-1API\s0"
+.IX Subsection "C API"
+The normal C \s-1API\s0 should work fine when used from \*(C+: both ev.h and the
+libev sources can be compiled as \*(C+. Therefore, code that uses the C \s-1API\s0
+will work fine.
+.PP
+Proper exception specifications might have to be added to callbacks passed
+to libev: exceptions may be thrown only from watcher callbacks, all
+other callbacks (allocator, syserr, loop acquire/release and periodic
+reschedule callbacks) must not throw exceptions, and might need a \f(CW\*(C`throw
+()\*(C'\fR specification. If you have code that needs to be compiled as both C
+and \*(C+ you can use the \f(CW\*(C`EV_THROW\*(C'\fR macro for this:
+.PP
+.Vb 6
+\& static void
+\& fatal_error (const char *msg) EV_THROW
+\& {
+\& perror (msg);
+\& abort ();
+\& }
+\&
+\& ...
+\& ev_set_syserr_cb (fatal_error);
+.Ve
+.PP
+The only \s-1API\s0 functions that can currently throw exceptions are \f(CW\*(C`ev_run\*(C'\fR,
+\&\f(CW\*(C`ev_invoke\*(C'\fR, \f(CW\*(C`ev_invoke_pending\*(C'\fR and \f(CW\*(C`ev_loop_destroy\*(C'\fR (the latter
+because it runs cleanup watchers).
+.PP
+Throwing exceptions in watcher callbacks is only supported if libev itself
+is compiled with a \*(C+ compiler or your C and \*(C+ environments allow
+throwing exceptions through C libraries (most do).
+.SS "\*(C+ \s-1API\s0"
+.IX Subsection " API"
+Libev comes with some simplistic wrapper classes for \*(C+ that mainly allow
+you to use some convenience methods to start/stop watchers and also change
+the callback model to a model using method callbacks on objects.
+.PP
+To use it,
+.PP
+.Vb 1
+\& #include <ev++.h>
+.Ve
+.PP
+This automatically includes \fIev.h\fR and puts all of its definitions (many
+of them macros) into the global namespace. All \*(C+ specific things are
+put into the \f(CW\*(C`ev\*(C'\fR namespace. It should support all the same embedding
+options as \fIev.h\fR, most notably \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR.
+.PP
+Care has been taken to keep the overhead low. The only data member the \*(C+
+classes add (compared to plain C\-style watchers) is the event loop pointer
+that the watcher is associated with (or no additional members at all if
+you disable \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR when embedding libev).
+.PP
+Currently, functions, static and non-static member functions and classes
+with \f(CW\*(C`operator ()\*(C'\fR can be used as callbacks. Other types should be easy
+to add as long as they only need one additional pointer for context. If
+you need support for other types of functors please contact the author
+(preferably after implementing it).
+.PP
+For all this to work, your \*(C+ compiler either has to use the same calling
+conventions as your C compiler (for static member functions), or you have
+to embed libev and compile libev itself as \*(C+.
+.PP
+Here is a list of things available in the \f(CW\*(C`ev\*(C'\fR namespace:
+.ie n .IP """ev::READ"", ""ev::WRITE"" etc." 4
+.el .IP "\f(CWev::READ\fR, \f(CWev::WRITE\fR etc." 4
+.IX Item "ev::READ, ev::WRITE etc."
+These are just enum values with the same values as the \f(CW\*(C`EV_READ\*(C'\fR etc.
+macros from \fIev.h\fR.
+.ie n .IP """ev::tstamp"", ""ev::now""" 4
+.el .IP "\f(CWev::tstamp\fR, \f(CWev::now\fR" 4
+.IX Item "ev::tstamp, ev::now"
+Aliases to the same types/functions as with the \f(CW\*(C`ev_\*(C'\fR prefix.
+.ie n .IP """ev::io"", ""ev::timer"", ""ev::periodic"", ""ev::idle"", ""ev::sig"" etc." 4
+.el .IP "\f(CWev::io\fR, \f(CWev::timer\fR, \f(CWev::periodic\fR, \f(CWev::idle\fR, \f(CWev::sig\fR etc." 4
+.IX Item "ev::io, ev::timer, ev::periodic, ev::idle, ev::sig etc."
+For each \f(CW\*(C`ev_TYPE\*(C'\fR watcher in \fIev.h\fR there is a corresponding class of
+the same name in the \f(CW\*(C`ev\*(C'\fR namespace, with the exception of \f(CW\*(C`ev_signal\*(C'\fR
+which is called \f(CW\*(C`ev::sig\*(C'\fR to avoid clashes with the \f(CW\*(C`signal\*(C'\fR macro
+defined by many implementations.
+.Sp
+All of those classes have these methods:
+.RS 4
+.IP "ev::TYPE::TYPE ()" 4
+.IX Item "ev::TYPE::TYPE ()"
+.PD 0
+.IP "ev::TYPE::TYPE (loop)" 4
+.IX Item "ev::TYPE::TYPE (loop)"
+.IP "ev::TYPE::~TYPE" 4
+.IX Item "ev::TYPE::~TYPE"
+.PD
+The constructor (optionally) takes an event loop to associate the watcher
+with. If it is omitted, it will use \f(CW\*(C`EV_DEFAULT\*(C'\fR.
+.Sp
+The constructor calls \f(CW\*(C`ev_init\*(C'\fR for you, which means you have to call the
+\&\f(CW\*(C`set\*(C'\fR method before starting it.
+.Sp
+It will not set a callback, however: You have to call the templated \f(CW\*(C`set\*(C'\fR
+method to set a callback before you can start the watcher.
+.Sp
+(The reason why you have to use a method is a limitation in \*(C+ which does
+not allow explicit template arguments for constructors).
+.Sp
+The destructor automatically stops the watcher if it is active.
+.IP "w\->set<class, &class::method> (object *)" 4
+.IX Item "w->set<class, &class::method> (object *)"
+This method sets the callback method to call. The method has to have a
+signature of \f(CW\*(C`void (*)(ev_TYPE &, int)\*(C'\fR, it receives the watcher as
+first argument and the \f(CW\*(C`revents\*(C'\fR as second. The object must be given as
+parameter and is stored in the \f(CW\*(C`data\*(C'\fR member of the watcher.
+.Sp
+This method synthesizes efficient thunking code to call your method from
+the C callback that libev requires. If your compiler can inline your
+callback (i.e. it is visible to it at the place of the \f(CW\*(C`set\*(C'\fR call and
+your compiler is good :), then the method will be fully inlined into the
+thunking function, making it as fast as a direct C callback.
+.Sp
+Example: simple class declaration and watcher initialisation
+.Sp
+.Vb 4
+\& struct myclass
+\& {
+\& void io_cb (ev::io &w, int revents) { }
+\& }
+\&
+\& myclass obj;
+\& ev::io iow;
+\& iow.set <myclass, &myclass::io_cb> (&obj);
+.Ve
+.IP "w\->set (object *)" 4
+.IX Item "w->set (object *)"
+This is a variation of a method callback \- leaving out the method to call
+will default the method to \f(CW\*(C`operator ()\*(C'\fR, which makes it possible to use
+functor objects without having to manually specify the \f(CW\*(C`operator ()\*(C'\fR all
+the time. Incidentally, you can then also leave out the template argument
+list.
+.Sp
+The \f(CW\*(C`operator ()\*(C'\fR method prototype must be \f(CW\*(C`void operator ()(watcher &w,
+int revents)\*(C'\fR.
+.Sp
+See the method\-\f(CW\*(C`set\*(C'\fR above for more details.
+.Sp
+Example: use a functor object as callback.
+.Sp
+.Vb 7
+\& struct myfunctor
+\& {
+\& void operator() (ev::io &w, int revents)
+\& {
+\& ...
+\& }
+\& }
+\&
+\& myfunctor f;
+\&
+\& ev::io w;
+\& w.set (&f);
+.Ve
+.IP "w\->set<function> (void *data = 0)" 4
+.IX Item "w->set<function> (void *data = 0)"
+Also sets a callback, but uses a static method or plain function as
+callback. The optional \f(CW\*(C`data\*(C'\fR argument will be stored in the watcher's
+\&\f(CW\*(C`data\*(C'\fR member and is free for you to use.
+.Sp
+The prototype of the \f(CW\*(C`function\*(C'\fR must be \f(CW\*(C`void (*)(ev::TYPE &w, int)\*(C'\fR.
+.Sp
+See the method\-\f(CW\*(C`set\*(C'\fR above for more details.
+.Sp
+Example: Use a plain function as callback.
+.Sp
+.Vb 2
+\& static void io_cb (ev::io &w, int revents) { }
+\& iow.set <io_cb> ();
+.Ve
+.IP "w\->set (loop)" 4
+.IX Item "w->set (loop)"
+Associates a different \f(CW\*(C`struct ev_loop\*(C'\fR with this watcher. You can only
+do this when the watcher is inactive (and not pending either).
+.IP "w\->set ([arguments])" 4
+.IX Item "w->set ([arguments])"
+Basically the same as \f(CW\*(C`ev_TYPE_set\*(C'\fR (except for \f(CW\*(C`ev::embed\*(C'\fR watchers>),
+with the same arguments. Either this method or a suitable start method
+must be called at least once. Unlike the C counterpart, an active watcher
+gets automatically stopped and restarted when reconfiguring it with this
+method.
+.Sp
+For \f(CW\*(C`ev::embed\*(C'\fR watchers this method is called \f(CW\*(C`set_embed\*(C'\fR, to avoid
+clashing with the \f(CW\*(C`set (loop)\*(C'\fR method.
+.IP "w\->start ()" 4
+.IX Item "w->start ()"
+Starts the watcher. Note that there is no \f(CW\*(C`loop\*(C'\fR argument, as the
+constructor already stores the event loop.
+.IP "w\->start ([arguments])" 4
+.IX Item "w->start ([arguments])"
+Instead of calling \f(CW\*(C`set\*(C'\fR and \f(CW\*(C`start\*(C'\fR methods separately, it is often
+convenient to wrap them in one call. Uses the same type of arguments as
+the configure \f(CW\*(C`set\*(C'\fR method of the watcher.
+.IP "w\->stop ()" 4
+.IX Item "w->stop ()"
+Stops the watcher if it is active. Again, no \f(CW\*(C`loop\*(C'\fR argument.
+.ie n .IP "w\->again () (""ev::timer"", ""ev::periodic"" only)" 4
+.el .IP "w\->again () (\f(CWev::timer\fR, \f(CWev::periodic\fR only)" 4
+.IX Item "w->again () (ev::timer, ev::periodic only)"
+For \f(CW\*(C`ev::timer\*(C'\fR and \f(CW\*(C`ev::periodic\*(C'\fR, this invokes the corresponding
+\&\f(CW\*(C`ev_TYPE_again\*(C'\fR function.
+.ie n .IP "w\->sweep () (""ev::embed"" only)" 4
+.el .IP "w\->sweep () (\f(CWev::embed\fR only)" 4
+.IX Item "w->sweep () (ev::embed only)"
+Invokes \f(CW\*(C`ev_embed_sweep\*(C'\fR.
+.ie n .IP "w\->update () (""ev::stat"" only)" 4
+.el .IP "w\->update () (\f(CWev::stat\fR only)" 4
+.IX Item "w->update () (ev::stat only)"
+Invokes \f(CW\*(C`ev_stat_stat\*(C'\fR.
+.RE
+.RS 4
+.RE
+.PP
+Example: Define a class with two I/O and idle watchers, start the I/O
+watchers in the constructor.
+.PP
+.Vb 5
+\& class myclass
+\& {
+\& ev::io io ; void io_cb (ev::io &w, int revents);
+\& ev::io io2 ; void io2_cb (ev::io &w, int revents);
+\& ev::idle idle; void idle_cb (ev::idle &w, int revents);
+\&
+\& myclass (int fd)
+\& {
+\& io .set <myclass, &myclass::io_cb > (this);
+\& io2 .set <myclass, &myclass::io2_cb > (this);
+\& idle.set <myclass, &myclass::idle_cb> (this);
+\&
+\& io.set (fd, ev::WRITE); // configure the watcher
+\& io.start (); // start it whenever convenient
+\&
+\& io2.start (fd, ev::READ); // set + start in one call
+\& }
+\& };
+.Ve
+.SH "OTHER LANGUAGE BINDINGS"
+.IX Header "OTHER LANGUAGE BINDINGS"
+Libev does not offer other language bindings itself, but bindings for a
+number of languages exist in the form of third-party packages. If you know
+any interesting language binding in addition to the ones listed here, drop
+me a note.
+.IP "Perl" 4
+.IX Item "Perl"
+The \s-1EV\s0 module implements the full libev \s-1API\s0 and is actually used to test
+libev. \s-1EV\s0 is developed together with libev. Apart from the \s-1EV\s0 core module,
+there are additional modules that implement libev-compatible interfaces
+to \f(CW\*(C`libadns\*(C'\fR (\f(CW\*(C`EV::ADNS\*(C'\fR, but \f(CW\*(C`AnyEvent::DNS\*(C'\fR is preferred nowadays),
+\&\f(CW\*(C`Net::SNMP\*(C'\fR (\f(CW\*(C`Net::SNMP::EV\*(C'\fR) and the \f(CW\*(C`libglib\*(C'\fR event core (\f(CW\*(C`Glib::EV\*(C'\fR
+and \f(CW\*(C`EV::Glib\*(C'\fR).
+.Sp
+It can be found and installed via \s-1CPAN,\s0 its homepage is at
+<http://software.schmorp.de/pkg/EV>.
+.IP "Python" 4
+.IX Item "Python"
+Python bindings can be found at <http://code.google.com/p/pyev/>. It
+seems to be quite complete and well-documented.
+.IP "Ruby" 4
+.IX Item "Ruby"
+Tony Arcieri has written a ruby extension that offers access to a subset
+of the libev \s-1API\s0 and adds file handle abstractions, asynchronous \s-1DNS\s0 and
+more on top of it. It can be found via gem servers. Its homepage is at
+<http://rev.rubyforge.org/>.
+.Sp
+Roger Pack reports that using the link order \f(CW\*(C`\-lws2_32 \-lmsvcrt\-ruby\-190\*(C'\fR
+makes rev work even on mingw.
+.IP "Haskell" 4
+.IX Item "Haskell"
+A haskell binding to libev is available at
+<http://hackage.haskell.org/cgi\-bin/hackage\-scripts/package/hlibev>.
+.IP "D" 4
+.IX Item "D"
+Leandro Lucarella has written a D language binding (\fIev.d\fR) for libev, to
+be found at <http://www.llucax.com.ar/proj/ev.d/index.html>.
+.IP "Ocaml" 4
+.IX Item "Ocaml"
+Erkki Seppala has written Ocaml bindings for libev, to be found at
+<http://modeemi.cs.tut.fi/~flux/software/ocaml\-ev/>.
+.IP "Lua" 4
+.IX Item "Lua"
+Brian Maher has written a partial interface to libev for lua (at the
+time of this writing, only \f(CW\*(C`ev_io\*(C'\fR and \f(CW\*(C`ev_timer\*(C'\fR), to be found at
+<http://github.com/brimworks/lua\-ev>.
+.IP "Javascript" 4
+.IX Item "Javascript"
+Node.js (<http://nodejs.org>) uses libev as the underlying event library.
+.IP "Others" 4
+.IX Item "Others"
+There are others, and I stopped counting.
+.SH "MACRO MAGIC"
+.IX Header "MACRO MAGIC"
+Libev can be compiled with a variety of options, the most fundamental
+of which is \f(CW\*(C`EV_MULTIPLICITY\*(C'\fR. This option determines whether (most)
+functions and callbacks have an initial \f(CW\*(C`struct ev_loop *\*(C'\fR argument.
+.PP
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+.ie n .IP """EV_A"", ""EV_A_""" 4
+.el .IP "\f(CWEV_A\fR, \f(CWEV_A_\fR" 4
+.IX Item "EV_A, EV_A_"
+This provides the loop \fIargument\fR for functions, if one is required (\*(L"ev
+loop argument\*(R"). The \f(CW\*(C`EV_A\*(C'\fR form is used when this is the sole argument,
+\&\f(CW\*(C`EV_A_\*(C'\fR is used when other arguments are following. Example:
+.Sp
+.Vb 3
+\& ev_unref (EV_A);
+\& ev_timer_add (EV_A_ watcher);
+\& ev_run (EV_A_ 0);
+.Ve
+.Sp
+It assumes the variable \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR is in scope,
+which is often provided by the following macro.
+.ie n .IP """EV_P"", ""EV_P_""" 4
+.el .IP "\f(CWEV_P\fR, \f(CWEV_P_\fR" 4
+.IX Item "EV_P, EV_P_"
+This provides the loop \fIparameter\fR for functions, if one is required (\*(L"ev
+loop parameter\*(R"). The \f(CW\*(C`EV_P\*(C'\fR form is used when this is the sole parameter,
+\&\f(CW\*(C`EV_P_\*(C'\fR is used when other parameters are following. Example:
+.Sp
+.Vb 2
+\& // this is how ev_unref is being declared
+\& static void ev_unref (EV_P);
+\&
+\& // this is how you can declare your typical callback
+\& static void cb (EV_P_ ev_timer *w, int revents)
+.Ve
+.Sp
+It declares a parameter \f(CW\*(C`loop\*(C'\fR of type \f(CW\*(C`struct ev_loop *\*(C'\fR, quite
+suitable for use with \f(CW\*(C`EV_A\*(C'\fR.
+.ie n .IP """EV_DEFAULT"", ""EV_DEFAULT_""" 4
+.el .IP "\f(CWEV_DEFAULT\fR, \f(CWEV_DEFAULT_\fR" 4
+.IX Item "EV_DEFAULT, EV_DEFAULT_"
+Similar to the other two macros, this gives you the value of the default
+loop, if multiple loops are supported (\*(L"ev loop default\*(R"). The default loop
+will be initialised if it isn't already initialised.
+.Sp
+For non-multiplicity builds, these macros do nothing, so you always have
+to initialise the loop somewhere.
+.ie n .IP """EV_DEFAULT_UC"", ""EV_DEFAULT_UC_""" 4
+.el .IP "\f(CWEV_DEFAULT_UC\fR, \f(CWEV_DEFAULT_UC_\fR" 4
+.IX Item "EV_DEFAULT_UC, EV_DEFAULT_UC_"
+Usage identical to \f(CW\*(C`EV_DEFAULT\*(C'\fR and \f(CW\*(C`EV_DEFAULT_\*(C'\fR, but requires that the
+default loop has been initialised (\f(CW\*(C`UC\*(C'\fR == unchecked). Their behaviour
+is undefined when the default loop has not been initialised by a previous
+execution of \f(CW\*(C`EV_DEFAULT\*(C'\fR, \f(CW\*(C`EV_DEFAULT_\*(C'\fR or \f(CW\*(C`ev_default_init (...)\*(C'\fR.
+.Sp
+It is often prudent to use \f(CW\*(C`EV_DEFAULT\*(C'\fR when initialising the first
+watcher in a function but use \f(CW\*(C`EV_DEFAULT_UC\*(C'\fR afterwards.
+.PP
+Example: Declare and initialise a check watcher, utilising the above
+macros so it will work regardless of whether multiple loops are supported
+or not.
+.PP
+.Vb 5
+\& static void
+\& check_cb (EV_P_ ev_timer *w, int revents)
+\& {
+\& ev_check_stop (EV_A_ w);
+\& }
+\&
+\& ev_check check;
+\& ev_check_init (&check, check_cb);
+\& ev_check_start (EV_DEFAULT_ &check);
+\& ev_run (EV_DEFAULT_ 0);
+.Ve
+.SH "EMBEDDING"
+.IX Header "EMBEDDING"
+Libev can (and often is) directly embedded into host
+applications. Examples of applications that embed it include the Deliantra
+Game Server, the \s-1EV\s0 perl module, the \s-1GNU\s0 Virtual Private Ethernet (gvpe)
+and rxvt-unicode.
+.PP
+The goal is to enable you to just copy the necessary files into your
+source directory without having to change even a single line in them, so
+you can easily upgrade by simply copying (or having a checked-out copy of
+libev somewhere in your source tree).
+.SS "\s-1FILESETS\s0"
+.IX Subsection "FILESETS"
+Depending on what features you need you need to include one or more sets of files
+in your application.
+.PP
+\fI\s-1CORE EVENT LOOP\s0\fR
+.IX Subsection "CORE EVENT LOOP"
+.PP
+To include only the libev core (all the \f(CW\*(C`ev_*\*(C'\fR functions), with manual
+configuration (no autoconf):
+.PP
+.Vb 2
+\& #define EV_STANDALONE 1
+\& #include "ev.c"
+.Ve
+.PP
+This will automatically include \fIev.h\fR, too, and should be done in a
+single C source file only to provide the function implementations. To use
+it, do the same for \fIev.h\fR in all files wishing to use this \s-1API \s0(best
+done by writing a wrapper around \fIev.h\fR that you can include instead and
+where you can put other configuration options):
+.PP
+.Vb 2
+\& #define EV_STANDALONE 1
+\& #include "ev.h"
+.Ve
+.PP
+Both header files and implementation files can be compiled with a \*(C+
+compiler (at least, that's a stated goal, and breakage will be treated
+as a bug).
+.PP
+You need the following files in your source tree, or in a directory
+in your include path (e.g. in libev/ when using \-Ilibev):
+.PP
+.Vb 4
+\& ev.h
+\& ev.c
+\& ev_vars.h
+\& ev_wrap.h
+\&
+\& ev_win32.c required on win32 platforms only
+\&
+\& ev_select.c only when select backend is enabled
+\& ev_poll.c only when poll backend is enabled
+\& ev_epoll.c only when the epoll backend is enabled
+\& ev_kqueue.c only when the kqueue backend is enabled
+\& ev_port.c only when the solaris port backend is enabled
+.Ve
+.PP
+\&\fIev.c\fR includes the backend files directly when enabled, so you only need
+to compile this single file.
+.PP
+\fI\s-1LIBEVENT COMPATIBILITY API\s0\fR
+.IX Subsection "LIBEVENT COMPATIBILITY API"
+.PP
+To include the libevent compatibility \s-1API,\s0 also include:
+.PP
+.Vb 1
+\& #include "event.c"
+.Ve
+.PP
+in the file including \fIev.c\fR, and:
+.PP
+.Vb 1
+\& #include "event.h"
+.Ve
+.PP
+in the files that want to use the libevent \s-1API.\s0 This also includes \fIev.h\fR.
+.PP
+You need the following additional files for this:
+.PP
+.Vb 2
+\& event.h
+\& event.c
+.Ve
+.PP
+\fI\s-1AUTOCONF SUPPORT\s0\fR
+.IX Subsection "AUTOCONF SUPPORT"
+.PP
+Instead of using \f(CW\*(C`EV_STANDALONE=1\*(C'\fR and providing your configuration in
+whatever way you want, you can also \f(CW\*(C`m4_include([libev.m4])\*(C'\fR in your
+\&\fIconfigure.ac\fR and leave \f(CW\*(C`EV_STANDALONE\*(C'\fR undefined. \fIev.c\fR will then
+include \fIconfig.h\fR and configure itself accordingly.
+.PP
+For this of course you need the m4 file:
+.PP
+.Vb 1
+\& libev.m4
+.Ve
+.SS "\s-1PREPROCESSOR SYMBOLS/MACROS\s0"
+.IX Subsection "PREPROCESSOR SYMBOLS/MACROS"
+Libev can be configured via a variety of preprocessor symbols you have to
+define before including (or compiling) any of its files. The default in
+the absence of autoconf is documented for every option.
+.PP
+Symbols marked with \*(L"(h)\*(R" do not change the \s-1ABI,\s0 and can have different
+values when compiling libev vs. including \fIev.h\fR, so it is permissible
+to redefine them before including \fIev.h\fR without breaking compatibility
+to a compiled library. All other symbols change the \s-1ABI,\s0 which means all
+users of libev and the libev code itself must be compiled with compatible
+settings.
+.IP "\s-1EV_COMPAT3 \s0(h)" 4
+.IX Item "EV_COMPAT3 (h)"
+Backwards compatibility is a major concern for libev. This is why this
+release of libev comes with wrappers for the functions and symbols that
+have been renamed between libev version 3 and 4.
+.Sp
+You can disable these wrappers (to test compatibility with future
+versions) by defining \f(CW\*(C`EV_COMPAT3\*(C'\fR to \f(CW0\fR when compiling your
+sources. This has the additional advantage that you can drop the \f(CW\*(C`struct\*(C'\fR
+from \f(CW\*(C`struct ev_loop\*(C'\fR declarations, as libev will provide an \f(CW\*(C`ev_loop\*(C'\fR
+typedef in that case.
+.Sp
+In some future version, the default for \f(CW\*(C`EV_COMPAT3\*(C'\fR will become \f(CW0\fR,
+and in some even more future version the compatibility code will be
+removed completely.
+.IP "\s-1EV_STANDALONE \s0(h)" 4
+.IX Item "EV_STANDALONE (h)"
+Must always be \f(CW1\fR if you do not use autoconf configuration, which
+keeps libev from including \fIconfig.h\fR, and it also defines dummy
+implementations for some libevent functions (such as logging, which is not
+supported). It will also not define any of the structs usually found in
+\&\fIevent.h\fR that are not directly supported by the libev core alone.
+.Sp
+In standalone mode, libev will still try to automatically deduce the
+configuration, but has to be more conservative.
+.IP "\s-1EV_USE_FLOOR\s0" 4
+.IX Item "EV_USE_FLOOR"
+If defined to be \f(CW1\fR, libev will use the \f(CW\*(C`floor ()\*(C'\fR function for its
+periodic reschedule calculations, otherwise libev will fall back on a
+portable (slower) implementation. If you enable this, you usually have to
+link against libm or something equivalent. Enabling this when the \f(CW\*(C`floor\*(C'\fR
+function is not available will fail, so the safe default is to not enable
+this.
+.IP "\s-1EV_USE_MONOTONIC\s0" 4
+.IX Item "EV_USE_MONOTONIC"
+If defined to be \f(CW1\fR, libev will try to detect the availability of the
+monotonic clock option at both compile time and runtime. Otherwise no
+use of the monotonic clock option will be attempted. If you enable this,
+you usually have to link against librt or something similar. Enabling it
+when the functionality isn't available is safe, though, although you have
+to make sure you link against any libraries where the \f(CW\*(C`clock_gettime\*(C'\fR
+function is hiding in (often \fI\-lrt\fR). See also \f(CW\*(C`EV_USE_CLOCK_SYSCALL\*(C'\fR.
+.IP "\s-1EV_USE_REALTIME\s0" 4
+.IX Item "EV_USE_REALTIME"
+If defined to be \f(CW1\fR, libev will try to detect the availability of the
+real-time clock option at compile time (and assume its availability
+at runtime if successful). Otherwise no use of the real-time clock
+option will be attempted. This effectively replaces \f(CW\*(C`gettimeofday\*(C'\fR
+by \f(CW\*(C`clock_get (CLOCK_REALTIME, ...)\*(C'\fR and will not normally affect
+correctness. See the note about libraries in the description of
+\&\f(CW\*(C`EV_USE_MONOTONIC\*(C'\fR, though. Defaults to the opposite value of
+\&\f(CW\*(C`EV_USE_CLOCK_SYSCALL\*(C'\fR.
+.IP "\s-1EV_USE_CLOCK_SYSCALL\s0" 4
+.IX Item "EV_USE_CLOCK_SYSCALL"
+If defined to be \f(CW1\fR, libev will try to use a direct syscall instead
+of calling the system-provided \f(CW\*(C`clock_gettime\*(C'\fR function. This option
+exists because on GNU/Linux, \f(CW\*(C`clock_gettime\*(C'\fR is in \f(CW\*(C`librt\*(C'\fR, but \f(CW\*(C`librt\*(C'\fR
+unconditionally pulls in \f(CW\*(C`libpthread\*(C'\fR, slowing down single-threaded
+programs needlessly. Using a direct syscall is slightly slower (in
+theory), because no optimised vdso implementation can be used, but avoids
+the pthread dependency. Defaults to \f(CW1\fR on GNU/Linux with glibc 2.x or
+higher, as it simplifies linking (no need for \f(CW\*(C`\-lrt\*(C'\fR).
+.IP "\s-1EV_USE_NANOSLEEP\s0" 4
+.IX Item "EV_USE_NANOSLEEP"
+If defined to be \f(CW1\fR, libev will assume that \f(CW\*(C`nanosleep ()\*(C'\fR is available
+and will use it for delays. Otherwise it will use \f(CW\*(C`select ()\*(C'\fR.
+.IP "\s-1EV_USE_EVENTFD\s0" 4
+.IX Item "EV_USE_EVENTFD"
+If defined to be \f(CW1\fR, then libev will assume that \f(CW\*(C`eventfd ()\*(C'\fR is
+available and will probe for kernel support at runtime. This will improve
+\&\f(CW\*(C`ev_signal\*(C'\fR and \f(CW\*(C`ev_async\*(C'\fR performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+.IP "\s-1EV_USE_SELECT\s0" 4
+.IX Item "EV_USE_SELECT"
+If undefined or defined to be \f(CW1\fR, libev will compile in support for the
+\&\f(CW\*(C`select\*(C'\fR(2) backend. No attempt at auto-detection will be done: if no
+other method takes over, select will be it. Otherwise the select backend
+will not be compiled in.
+.IP "\s-1EV_SELECT_USE_FD_SET\s0" 4
+.IX Item "EV_SELECT_USE_FD_SET"
+If defined to \f(CW1\fR, then the select backend will use the system \f(CW\*(C`fd_set\*(C'\fR
+structure. This is useful if libev doesn't compile due to a missing
+\&\f(CW\*(C`NFDBITS\*(C'\fR or \f(CW\*(C`fd_mask\*(C'\fR definition or it mis-guesses the bitset layout
+on exotic systems. This usually limits the range of file descriptors to
+some low limit such as 1024 or might have other limitations (winsocket
+only allows 64 sockets). The \f(CW\*(C`FD_SETSIZE\*(C'\fR macro, set before compilation,
+configures the maximum size of the \f(CW\*(C`fd_set\*(C'\fR.
+.IP "\s-1EV_SELECT_IS_WINSOCKET\s0" 4
+.IX Item "EV_SELECT_IS_WINSOCKET"
+When defined to \f(CW1\fR, the select backend will assume that
+select/socket/connect etc. don't understand file descriptors but
+wants osf handles on win32 (this is the case when the select to
+be used is the winsock select). This means that it will call
+\&\f(CW\*(C`_get_osfhandle\*(C'\fR on the fd to convert it to an \s-1OS\s0 handle. Otherwise,
+it is assumed that all these functions actually work on fds, even
+on win32. Should not be defined on non\-win32 platforms.
+.IP "\s-1EV_FD_TO_WIN32_HANDLE\s0(fd)" 4
+.IX Item "EV_FD_TO_WIN32_HANDLE(fd)"
+If \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR is enabled, then libev needs a way to map
+file descriptors to socket handles. When not defining this symbol (the
+default), then libev will call \f(CW\*(C`_get_osfhandle\*(C'\fR, which is usually
+correct. In some cases, programs use their own file descriptor management,
+in which case they can provide this function to map fds to socket handles.
+.IP "\s-1EV_WIN32_HANDLE_TO_FD\s0(handle)" 4
+.IX Item "EV_WIN32_HANDLE_TO_FD(handle)"
+If \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR then libev maps handles to file descriptors
+using the standard \f(CW\*(C`_open_osfhandle\*(C'\fR function. For programs implementing
+their own fd to handle mapping, overwriting this function makes it easier
+to do so. This can be done by defining this macro to an appropriate value.
+.IP "\s-1EV_WIN32_CLOSE_FD\s0(fd)" 4
+.IX Item "EV_WIN32_CLOSE_FD(fd)"
+If programs implement their own fd to handle mapping on win32, then this
+macro can be used to override the \f(CW\*(C`close\*(C'\fR function, useful to unregister
+file descriptors again. Note that the replacement function has to close
+the underlying \s-1OS\s0 handle.
+.IP "\s-1EV_USE_WSASOCKET\s0" 4
+.IX Item "EV_USE_WSASOCKET"
+If defined to be \f(CW1\fR, libev will use \f(CW\*(C`WSASocket\*(C'\fR to create its internal
+communication socket, which works better in some environments. Otherwise,
+the normal \f(CW\*(C`socket\*(C'\fR function will be used, which works better in other
+environments.
+.IP "\s-1EV_USE_POLL\s0" 4
+.IX Item "EV_USE_POLL"
+If defined to be \f(CW1\fR, libev will compile in support for the \f(CW\*(C`poll\*(C'\fR(2)
+backend. Otherwise it will be enabled on non\-win32 platforms. It
+takes precedence over select.
+.IP "\s-1EV_USE_EPOLL\s0" 4
+.IX Item "EV_USE_EPOLL"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux
+\&\f(CW\*(C`epoll\*(C'\fR(7) backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for GNU/Linux systems. If undefined, it will be enabled if the
+headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+.IP "\s-1EV_USE_KQUEUE\s0" 4
+.IX Item "EV_USE_KQUEUE"
+If defined to be \f(CW1\fR, libev will compile in support for the \s-1BSD\s0 style
+\&\f(CW\*(C`kqueue\*(C'\fR(2) backend. Its actual availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for \s-1BSD\s0 and BSD-like systems, although on most BSDs kqueue only
+supports some types of fds correctly (the only platform we found that
+supports ptys for example was NetBSD), so kqueue might be compiled in, but
+not be used unless explicitly requested. The best way to use it is to find
+out whether kqueue supports your type of fd properly and use an embedded
+kqueue loop.
+.IP "\s-1EV_USE_PORT\s0" 4
+.IX Item "EV_USE_PORT"
+If defined to be \f(CW1\fR, libev will compile in support for the Solaris
+10 port style backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for Solaris 10 systems.
+.IP "\s-1EV_USE_DEVPOLL\s0" 4
+.IX Item "EV_USE_DEVPOLL"
+Reserved for future expansion, works like the \s-1USE\s0 symbols above.
+.IP "\s-1EV_USE_INOTIFY\s0" 4
+.IX Item "EV_USE_INOTIFY"
+If defined to be \f(CW1\fR, libev will compile in support for the Linux inotify
+interface to speed up \f(CW\*(C`ev_stat\*(C'\fR watchers. Its actual availability will
+be detected at runtime. If undefined, it will be enabled if the headers
+indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+.IP "\s-1EV_NO_SMP\s0" 4
+.IX Item "EV_NO_SMP"
+If defined to be \f(CW1\fR, libev will assume that memory is always coherent
+between threads, that is, threads can be used, but threads never run on
+different cpus (or different cpu cores). This reduces dependencies
+and makes libev faster.
+.IP "\s-1EV_NO_THREADS\s0" 4
+.IX Item "EV_NO_THREADS"
+If defined to be \f(CW1\fR, libev will assume that it will never be called from
+different threads (that includes signal handlers), which is a stronger
+assumption than \f(CW\*(C`EV_NO_SMP\*(C'\fR, above. This reduces dependencies and makes
+libev faster.
+.IP "\s-1EV_ATOMIC_T\s0" 4
+.IX Item "EV_ATOMIC_T"
+Libev requires an integer type (suitable for storing \f(CW0\fR or \f(CW1\fR) whose
+access is atomic with respect to other threads or signal contexts. No
+such type is easily found in the C language, so you can provide your own
+type that you know is safe for your purposes. It is used both for signal
+handler \*(L"locking\*(R" as well as for signal and thread safety in \f(CW\*(C`ev_async\*(C'\fR
+watchers.
+.Sp
+In the absence of this define, libev will use \f(CW\*(C`sig_atomic_t volatile\*(C'\fR
+(from \fIsignal.h\fR), which is usually good enough on most platforms.
+.IP "\s-1EV_H \s0(h)" 4
+.IX Item "EV_H (h)"
+The name of the \fIev.h\fR header file used to include it. The default if
+undefined is \f(CW"ev.h"\fR in \fIevent.h\fR, \fIev.c\fR and \fIev++.h\fR. This can be
+used to virtually rename the \fIev.h\fR header file in case of conflicts.
+.IP "\s-1EV_CONFIG_H \s0(h)" 4
+.IX Item "EV_CONFIG_H (h)"
+If \f(CW\*(C`EV_STANDALONE\*(C'\fR isn't \f(CW1\fR, this variable can be used to override
+\&\fIev.c\fR's idea of where to find the \fIconfig.h\fR file, similarly to
+\&\f(CW\*(C`EV_H\*(C'\fR, above.
+.IP "\s-1EV_EVENT_H \s0(h)" 4
+.IX Item "EV_EVENT_H (h)"
+Similarly to \f(CW\*(C`EV_H\*(C'\fR, this macro can be used to override \fIevent.c\fR's idea
+of how the \fIevent.h\fR header can be found, the default is \f(CW"event.h"\fR.
+.IP "\s-1EV_PROTOTYPES \s0(h)" 4
+.IX Item "EV_PROTOTYPES (h)"
+If defined to be \f(CW0\fR, then \fIev.h\fR will not define any function
+prototypes, but still define all the structs and other symbols. This is
+occasionally useful if you want to provide your own wrapper functions
+around libev functions.
+.IP "\s-1EV_MULTIPLICITY\s0" 4
+.IX Item "EV_MULTIPLICITY"
+If undefined or defined to \f(CW1\fR, then all event-loop-specific functions
+will have the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument, and you can create
+additional independent event loops. Otherwise there will be no support
+for multiple event loops and there is no first event loop pointer
+argument. Instead, all functions act on the single default loop.
+.Sp
+Note that \f(CW\*(C`EV_DEFAULT\*(C'\fR and \f(CW\*(C`EV_DEFAULT_\*(C'\fR will no longer provide a
+default loop when multiplicity is switched off \- you always have to
+initialise the loop manually in this case.
+.IP "\s-1EV_MINPRI\s0" 4
+.IX Item "EV_MINPRI"
+.PD 0
+.IP "\s-1EV_MAXPRI\s0" 4
+.IX Item "EV_MAXPRI"
+.PD
+The range of allowed priorities. \f(CW\*(C`EV_MINPRI\*(C'\fR must be smaller or equal to
+\&\f(CW\*(C`EV_MAXPRI\*(C'\fR, but otherwise there are no non-obvious limitations. You can
+provide for more priorities by overriding those symbols (usually defined
+to be \f(CW\*(C`\-2\*(C'\fR and \f(CW2\fR, respectively).
+.Sp
+When doing priority-based operations, libev usually has to linearly search
+all the priorities, so having many of them (hundreds) uses a lot of space
+and time, so using the defaults of five priorities (\-2 .. +2) is usually
+fine.
+.Sp
+If your embedding application does not need any priorities, defining these
+both to \f(CW0\fR will save some memory and \s-1CPU.\s0
+.IP "\s-1EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE.\s0" 4
+.IX Item "EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE, EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE, EV_ASYNC_ENABLE, EV_CHILD_ENABLE."
+If undefined or defined to be \f(CW1\fR (and the platform supports it), then
+the respective watcher type is supported. If defined to be \f(CW0\fR, then it
+is not. Disabling watcher types mainly saves code size.
+.IP "\s-1EV_FEATURES\s0" 4
+.IX Item "EV_FEATURES"
+If you need to shave off some kilobytes of code at the expense of some
+speed (but with the full \s-1API\s0), you can define this symbol to request
+certain subsets of functionality. The default is to enable all features
+that can be enabled on the platform.
+.Sp
+A typical way to use this symbol is to define it to \f(CW0\fR (or to a bitset
+with some broad features you want) and then selectively re-enable
+additional parts you want, for example if you want everything minimal,
+but multiple event loop support, async and child watchers and the poll
+backend, use this:
+.Sp
+.Vb 5
+\& #define EV_FEATURES 0
+\& #define EV_MULTIPLICITY 1
+\& #define EV_USE_POLL 1
+\& #define EV_CHILD_ENABLE 1
+\& #define EV_ASYNC_ENABLE 1
+.Ve
+.Sp
+The actual value is a bitset, it can be a combination of the following
+values (by default, all of these are enabled):
+.RS 4
+.ie n .IP "1 \- faster/larger code" 4
+.el .IP "\f(CW1\fR \- faster/larger code" 4
+.IX Item "1 - faster/larger code"
+Use larger code to speed up some operations.
+.Sp
+Currently this is used to override some inlining decisions (enlarging the
+code size by roughly 30% on amd64).
+.Sp
+When optimising for size, use of compiler flags such as \f(CW\*(C`\-Os\*(C'\fR with
+gcc is recommended, as well as \f(CW\*(C`\-DNDEBUG\*(C'\fR, as libev contains a number of
+assertions.
+.Sp
+The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler
+(e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR).
+.ie n .IP "2 \- faster/larger data structures" 4
+.el .IP "\f(CW2\fR \- faster/larger data structures" 4
+.IX Item "2 - faster/larger data structures"
+Replaces the small 2\-heap for timer management by a faster 4\-heap, larger
+hash table sizes and so on. This will usually further increase code size
+and can additionally have an effect on the size of data structures at
+runtime.
+.Sp
+The default is off when \f(CW\*(C`_\|_OPTIMIZE_SIZE_\|_\*(C'\fR is defined by your compiler
+(e.g. gcc with \f(CW\*(C`\-Os\*(C'\fR).
+.ie n .IP "4 \- full \s-1API\s0 configuration" 4
+.el .IP "\f(CW4\fR \- full \s-1API\s0 configuration" 4
+.IX Item "4 - full API configuration"
+This enables priorities (sets \f(CW\*(C`EV_MAXPRI\*(C'\fR=2 and \f(CW\*(C`EV_MINPRI\*(C'\fR=\-2), and
+enables multiplicity (\f(CW\*(C`EV_MULTIPLICITY\*(C'\fR=1).
+.ie n .IP "8 \- full \s-1API\s0" 4
+.el .IP "\f(CW8\fR \- full \s-1API\s0" 4
+.IX Item "8 - full API"
+This enables a lot of the \*(L"lesser used\*(R" \s-1API\s0 functions. See \f(CW\*(C`ev.h\*(C'\fR for
+details on which parts of the \s-1API\s0 are still available without this
+feature, and do not complain if this subset changes over time.
+.ie n .IP "16 \- enable all optional watcher types" 4
+.el .IP "\f(CW16\fR \- enable all optional watcher types" 4
+.IX Item "16 - enable all optional watcher types"
+Enables all optional watcher types. If you want to selectively enable
+only some watcher types other than I/O and timers (e.g. prepare,
+embed, async, child...) you can enable them manually by defining
+\&\f(CW\*(C`EV_watchertype_ENABLE\*(C'\fR to \f(CW1\fR instead.
+.ie n .IP "32 \- enable all backends" 4
+.el .IP "\f(CW32\fR \- enable all backends" 4
+.IX Item "32 - enable all backends"
+This enables all backends \- without this feature, you need to enable at
+least one backend manually (\f(CW\*(C`EV_USE_SELECT\*(C'\fR is a good choice).
+.ie n .IP "64 \- enable OS-specific ""helper"" APIs" 4
+.el .IP "\f(CW64\fR \- enable OS-specific ``helper'' APIs" 4
+.IX Item "64 - enable OS-specific helper APIs"
+Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
+default.
+.RE
+.RS 4
+.Sp
+Compiling with \f(CW\*(C`gcc \-Os \-DEV_STANDALONE \-DEV_USE_EPOLL=1 \-DEV_FEATURES=0\*(C'\fR
+reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
+code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
+watchers, timers and monotonic clock support.
+.Sp
+With an intelligent-enough linker (gcc+binutils are intelligent enough
+when you use \f(CW\*(C`\-Wl,\-\-gc\-sections \-ffunction\-sections\*(C'\fR) functions unused by
+your program might be left out as well \- a binary starting a timer and an
+I/O watcher then might come out at only 5Kb.
+.RE
+.IP "\s-1EV_API_STATIC\s0" 4
+.IX Item "EV_API_STATIC"
+If this symbol is defined (by default it is not), then all identifiers
+will have static linkage. This means that libev will not export any
+identifiers, and you cannot link against libev anymore. This can be useful
+when you embed libev, only want to use libev functions in a single file,
+and do not want its identifiers to be visible.
+.Sp
+To use this, define \f(CW\*(C`EV_API_STATIC\*(C'\fR and include \fIev.c\fR in the file that
+wants to use libev.
+.Sp
+This option only works when libev is compiled with a C compiler, as \*(C+
+doesn't support the required declaration syntax.
+.IP "\s-1EV_AVOID_STDIO\s0" 4
+.IX Item "EV_AVOID_STDIO"
+If this is set to \f(CW1\fR at compiletime, then libev will avoid using stdio
+functions (printf, scanf, perror etc.). This will increase the code size
+somewhat, but if your program doesn't otherwise depend on stdio and your
+libc allows it, this avoids linking in the stdio library which is quite
+big.
+.Sp
+Note that error messages might become less precise when this option is
+enabled.
+.IP "\s-1EV_NSIG\s0" 4
+.IX Item "EV_NSIG"
+The highest supported signal number, +1 (or, the number of
+signals): Normally, libev tries to deduce the maximum number of signals
+automatically, but sometimes this fails, in which case it can be
+specified. Also, using a lower number than detected (\f(CW32\fR should be
+good for about any system in existence) can save some memory, as libev
+statically allocates some 12\-24 bytes per signal number.
+.IP "\s-1EV_PID_HASHSIZE\s0" 4
+.IX Item "EV_PID_HASHSIZE"
+\&\f(CW\*(C`ev_child\*(C'\fR watchers use a small hash table to distribute workload by
+pid. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_FEATURES\*(C'\fR disabled),
+usually more than enough. If you need to manage thousands of children you
+might want to increase this value (\fImust\fR be a power of two).
+.IP "\s-1EV_INOTIFY_HASHSIZE\s0" 4
+.IX Item "EV_INOTIFY_HASHSIZE"
+\&\f(CW\*(C`ev_stat\*(C'\fR watchers use a small hash table to distribute workload by
+inotify watch id. The default size is \f(CW16\fR (or \f(CW1\fR with \f(CW\*(C`EV_FEATURES\*(C'\fR
+disabled), usually more than enough. If you need to manage thousands of
+\&\f(CW\*(C`ev_stat\*(C'\fR watchers you might want to increase this value (\fImust\fR be a
+power of two).
+.IP "\s-1EV_USE_4HEAP\s0" 4
+.IX Item "EV_USE_4HEAP"
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev uses a 4\-heap when this symbol is defined
+to \f(CW1\fR. The 4\-heap uses more complicated (longer) code but has noticeably
+faster performance with many (thousands) of watchers.
+.Sp
+The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
+will be \f(CW0\fR.
+.IP "\s-1EV_HEAP_CACHE_AT\s0" 4
+.IX Item "EV_HEAP_CACHE_AT"
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev can cache the timestamp (\fIat\fR) within
+the heap structure (selected by defining \f(CW\*(C`EV_HEAP_CACHE_AT\*(C'\fR to \f(CW1\fR),
+which uses 8\-12 bytes more per watcher and a few hundred bytes more code,
+but avoids random read accesses on heap changes. This improves performance
+noticeably with many (hundreds) of watchers.
+.Sp
+The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
+will be \f(CW0\fR.
+.IP "\s-1EV_VERIFY\s0" 4
+.IX Item "EV_VERIFY"
+Controls how much internal verification (see \f(CW\*(C`ev_verify ()\*(C'\fR) will
+be done: If set to \f(CW0\fR, no internal verification code will be compiled
+in. If set to \f(CW1\fR, then verification code will be compiled in, but not
+called. If set to \f(CW2\fR, then the internal verification code will be
+called once per loop, which can slow down libev. If set to \f(CW3\fR, then the
+verification code will be called very frequently, which will slow down
+libev considerably.
+.Sp
+The default is \f(CW1\fR, unless \f(CW\*(C`EV_FEATURES\*(C'\fR overrides it, in which case it
+will be \f(CW0\fR.
+.IP "\s-1EV_COMMON\s0" 4
+.IX Item "EV_COMMON"
+By default, all watchers have a \f(CW\*(C`void *data\*(C'\fR member. By redefining
+this macro to something else you can include more and other types of
+members. You have to define it each time you include one of the files,
+though, and it must be identical each time.
+.Sp
+For example, the perl \s-1EV\s0 module uses something like this:
+.Sp
+.Vb 3
+\& #define EV_COMMON \e
+\& SV *self; /* contains this struct */ \e
+\& SV *cb_sv, *fh /* note no trailing ";" */
+.Ve
+.IP "\s-1EV_CB_DECLARE \s0(type)" 4
+.IX Item "EV_CB_DECLARE (type)"
+.PD 0
+.IP "\s-1EV_CB_INVOKE \s0(watcher, revents)" 4
+.IX Item "EV_CB_INVOKE (watcher, revents)"
+.IP "ev_set_cb (ev, cb)" 4
+.IX Item "ev_set_cb (ev, cb)"
+.PD
+Can be used to change the callback member declaration in each watcher,
+and the way callbacks are invoked and set. Must expand to a struct member
+definition and a statement, respectively. See the \fIev.h\fR header file for
+their default definitions. One possible use for overriding these is to
+avoid the \f(CW\*(C`struct ev_loop *\*(C'\fR as first argument in all cases, or to use
+method calls instead of plain function calls in \*(C+.
+.SS "\s-1EXPORTED API SYMBOLS\s0"
+.IX Subsection "EXPORTED API SYMBOLS"
+If you need to re-export the \s-1API \s0(e.g. via a \s-1DLL\s0) and you need a list of
+exported symbols, you can use the provided \fISymbol.*\fR files which list
+all public symbols, one per line:
+.PP
+.Vb 2
+\& Symbols.ev for libev proper
+\& Symbols.event for the libevent emulation
+.Ve
+.PP
+This can also be used to rename all public symbols to avoid clashes with
+multiple versions of libev linked together (which is obviously bad in
+itself, but sometimes it is inconvenient to avoid this).
+.PP
+A sed command like this will create wrapper \f(CW\*(C`#define\*(C'\fR's that you need to
+include before including \fIev.h\fR:
+.PP
+.Vb 1
+\& <Symbols.ev sed \-e "s/.*/#define & myprefix_&/" >wrap.h
+.Ve
+.PP
+This would create a file \fIwrap.h\fR which essentially looks like this:
+.PP
+.Vb 4
+\& #define ev_backend myprefix_ev_backend
+\& #define ev_check_start myprefix_ev_check_start
+\& #define ev_check_stop myprefix_ev_check_stop
+\& ...
+.Ve
+.SS "\s-1EXAMPLES\s0"
+.IX Subsection "EXAMPLES"
+For a real-world example of a program the includes libev
+verbatim, you can have a look at the \s-1EV\s0 perl module
+(<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
+the \fIlibev/\fR subdirectory and includes them in the \fI\s-1EV/EVAPI\s0.h\fR (public
+interface) and \fI\s-1EV\s0.xs\fR (implementation) files. Only the \fI\s-1EV\s0.xs\fR file
+will be compiled. It is pretty complex because it provides its own header
+file.
+.PP
+The usage in rxvt-unicode is simpler. It has a \fIev_cpp.h\fR header file
+that everybody includes and which overrides some configure choices:
+.PP
+.Vb 8
+\& #define EV_FEATURES 8
+\& #define EV_USE_SELECT 1
+\& #define EV_PREPARE_ENABLE 1
+\& #define EV_IDLE_ENABLE 1
+\& #define EV_SIGNAL_ENABLE 1
+\& #define EV_CHILD_ENABLE 1
+\& #define EV_USE_STDEXCEPT 0
+\& #define EV_CONFIG_H <config.h>
+\&
+\& #include "ev++.h"
+.Ve
+.PP
+And a \fIev_cpp.C\fR implementation file that contains libev proper and is compiled:
+.PP
+.Vb 2
+\& #include "ev_cpp.h"
+\& #include "ev.c"
+.Ve
+.SH "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT"
+.IX Header "INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT"
+.SS "\s-1THREADS AND COROUTINES\s0"
+.IX Subsection "THREADS AND COROUTINES"
+\fI\s-1THREADS\s0\fR
+.IX Subsection "THREADS"
+.PP
+All libev functions are reentrant and thread-safe unless explicitly
+documented otherwise, but libev implements no locking itself. This means
+that you can use as many loops as you want in parallel, as long as there
+are no concurrent calls into any libev function with the same loop
+parameter (\f(CW\*(C`ev_default_*\*(C'\fR calls have an implicit default loop parameter,
+of course): libev guarantees that different event loops share no data
+structures that need any locking.
+.PP
+Or to put it differently: calls with different loop parameters can be done
+concurrently from multiple threads, calls with the same loop parameter
+must be done serially (but can be done from different threads, as long as
+only one thread ever is inside a call at any point in time, e.g. by using
+a mutex per loop).
+.PP
+Specifically to support threads (and signal handlers), libev implements
+so-called \f(CW\*(C`ev_async\*(C'\fR watchers, which allow some limited form of
+concurrency on the same event loop, namely waking it up \*(L"from the
+outside\*(R".
+.PP
+If you want to know which design (one loop, locking, or multiple loops
+without or something else still) is best for your problem, then I cannot
+help you, but here is some generic advice:
+.IP "\(bu" 4
+most applications have a main thread: use the default libev loop
+in that thread, or create a separate thread running only the default loop.
+.Sp
+This helps integrating other libraries or software modules that use libev
+themselves and don't care/know about threading.
+.IP "\(bu" 4
+one loop per thread is usually a good model.
+.Sp
+Doing this is almost never wrong, sometimes a better-performance model
+exists, but it is always a good start.
+.IP "\(bu" 4
+other models exist, such as the leader/follower pattern, where one
+loop is handed through multiple threads in a kind of round-robin fashion.
+.Sp
+Choosing a model is hard \- look around, learn, know that usually you can do
+better than you currently do :\-)
+.IP "\(bu" 4
+often you need to talk to some other thread which blocks in the
+event loop.
+.Sp
+\&\f(CW\*(C`ev_async\*(C'\fR watchers can be used to wake them up from other threads safely
+(or from signal contexts...).
+.Sp
+An example use would be to communicate signals or other events that only
+work in the default loop by registering the signal watcher with the
+default loop and triggering an \f(CW\*(C`ev_async\*(C'\fR watcher from the default loop
+watcher callback into the event loop interested in the signal.
+.PP
+See also \*(L"\s-1THREAD LOCKING EXAMPLE\*(R"\s0.
+.PP
+\fI\s-1COROUTINES\s0\fR
+.IX Subsection "COROUTINES"
+.PP
+Libev is very accommodating to coroutines (\*(L"cooperative threads\*(R"):
+libev fully supports nesting calls to its functions from different
+coroutines (e.g. you can call \f(CW\*(C`ev_run\*(C'\fR on the same loop from two
+different coroutines, and switch freely between both coroutines running
+the loop, as long as you don't confuse yourself). The only exception is
+that you must not do this from \f(CW\*(C`ev_periodic\*(C'\fR reschedule callbacks.
+.PP
+Care has been taken to ensure that libev does not keep local state inside
+\&\f(CW\*(C`ev_run\*(C'\fR, and other calls do not usually allow for coroutine switches as
+they do not call any callbacks.
+.SS "\s-1COMPILER WARNINGS\s0"
+.IX Subsection "COMPILER WARNINGS"
+Depending on your compiler and compiler settings, you might get no or a
+lot of warnings when compiling libev code. Some people are apparently
+scared by this.
+.PP
+However, these are unavoidable for many reasons. For one, each compiler
+has different warnings, and each user has different tastes regarding
+warning options. \*(L"Warn-free\*(R" code therefore cannot be a goal except when
+targeting a specific compiler and compiler-version.
+.PP
+Another reason is that some compiler warnings require elaborate
+workarounds, or other changes to the code that make it less clear and less
+maintainable.
+.PP
+And of course, some compiler warnings are just plain stupid, or simply
+wrong (because they don't actually warn about the condition their message
+seems to warn about). For example, certain older gcc versions had some
+warnings that resulted in an extreme number of false positives. These have
+been fixed, but some people still insist on making code warn-free with
+such buggy versions.
+.PP
+While libev is written to generate as few warnings as possible,
+\&\*(L"warn-free\*(R" code is not a goal, and it is recommended not to build libev
+with any compiler warnings enabled unless you are prepared to cope with
+them (e.g. by ignoring them). Remember that warnings are just that:
+warnings, not errors, or proof of bugs.
+.SS "\s-1VALGRIND\s0"
+.IX Subsection "VALGRIND"
+Valgrind has a special section here because it is a popular tool that is
+highly useful. Unfortunately, valgrind reports are very hard to interpret.
+.PP
+If you think you found a bug (memory leak, uninitialised data access etc.)
+in libev, then check twice: If valgrind reports something like:
+.PP
+.Vb 3
+\& ==2274== definitely lost: 0 bytes in 0 blocks.
+\& ==2274== possibly lost: 0 bytes in 0 blocks.
+\& ==2274== still reachable: 256 bytes in 1 blocks.
+.Ve
+.PP
+Then there is no memory leak, just as memory accounted to global variables
+is not a memleak \- the memory is still being referenced, and didn't leak.
+.PP
+Similarly, under some circumstances, valgrind might report kernel bugs
+as if it were a bug in libev (e.g. in realloc or in the poll backend,
+although an acceptable workaround has been found here), or it might be
+confused.
+.PP
+Keep in mind that valgrind is a very good tool, but only a tool. Don't
+make it into some kind of religion.
+.PP
+If you are unsure about something, feel free to contact the mailing list
+with the full valgrind report and an explanation on why you think this
+is a bug in libev (best check the archives, too :). However, don't be
+annoyed when you get a brisk \*(L"this is no bug\*(R" answer and take the chance
+of learning how to interpret valgrind properly.
+.PP
+If you need, for some reason, empty reports from valgrind for your project
+I suggest using suppression lists.
+.SH "PORTABILITY NOTES"
+.IX Header "PORTABILITY NOTES"
+.SS "\s-1GNU/LINUX 32 BIT LIMITATIONS\s0"
+.IX Subsection "GNU/LINUX 32 BIT LIMITATIONS"
+GNU/Linux is the only common platform that supports 64 bit file/large file
+interfaces but \fIdisables\fR them by default.
+.PP
+That means that libev compiled in the default environment doesn't support
+files larger than 2GiB or so, which mainly affects \f(CW\*(C`ev_stat\*(C'\fR watchers.
+.PP
+Unfortunately, many programs try to work around this GNU/Linux issue
+by enabling the large file \s-1API,\s0 which makes them incompatible with the
+standard libev compiled for their system.
+.PP
+Likewise, libev cannot enable the large file \s-1API\s0 itself as this would
+suddenly make it incompatible to the default compile time environment,
+i.e. all programs not using special compile switches.
+.SS "\s-1OS/X AND DARWIN BUGS\s0"
+.IX Subsection "OS/X AND DARWIN BUGS"
+The whole thing is a bug if you ask me \- basically any system interface
+you touch is broken, whether it is locales, poll, kqueue or even the
+OpenGL drivers.
+.PP
+\fI\f(CI\*(C`kqueue\*(C'\fI is buggy\fR
+.IX Subsection "kqueue is buggy"
+.PP
+The kqueue syscall is broken in all known versions \- most versions support
+only sockets, many support pipes.
+.PP
+Libev tries to work around this by not using \f(CW\*(C`kqueue\*(C'\fR by default on this
+rotten platform, but of course you can still ask for it when creating a
+loop \- embedding a socket-only kqueue loop into a select-based one is
+probably going to work well.
+.PP
+\fI\f(CI\*(C`poll\*(C'\fI is buggy\fR
+.IX Subsection "poll is buggy"
+.PP
+Instead of fixing \f(CW\*(C`kqueue\*(C'\fR, Apple replaced their (working) \f(CW\*(C`poll\*(C'\fR
+implementation by something calling \f(CW\*(C`kqueue\*(C'\fR internally around the 10.5.6
+release, so now \f(CW\*(C`kqueue\*(C'\fR \fIand\fR \f(CW\*(C`poll\*(C'\fR are broken.
+.PP
+Libev tries to work around this by not using \f(CW\*(C`poll\*(C'\fR by default on
+this rotten platform, but of course you can still ask for it when creating
+a loop.
+.PP
+\fI\f(CI\*(C`select\*(C'\fI is buggy\fR
+.IX Subsection "select is buggy"
+.PP
+All that's left is \f(CW\*(C`select\*(C'\fR, and of course Apple found a way to fuck this
+one up as well: On \s-1OS/X, \s0\f(CW\*(C`select\*(C'\fR actively limits the number of file
+descriptors you can pass in to 1024 \- your program suddenly crashes when
+you use more.
+.PP
+There is an undocumented \*(L"workaround\*(R" for this \- defining
+\&\f(CW\*(C`_DARWIN_UNLIMITED_SELECT\*(C'\fR, which libev tries to use, so select \fIshould\fR
+work on \s-1OS/X.\s0
+.SS "\s-1SOLARIS PROBLEMS AND WORKAROUNDS\s0"
+.IX Subsection "SOLARIS PROBLEMS AND WORKAROUNDS"
+\fI\f(CI\*(C`errno\*(C'\fI reentrancy\fR
+.IX Subsection "errno reentrancy"
+.PP
+The default compile environment on Solaris is unfortunately so
+thread-unsafe that you can't even use components/libraries compiled
+without \f(CW\*(C`\-D_REENTRANT\*(C'\fR in a threaded program, which, of course, isn't
+defined by default. A valid, if stupid, implementation choice.
+.PP
+If you want to use libev in threaded environments you have to make sure
+it's compiled with \f(CW\*(C`_REENTRANT\*(C'\fR defined.
+.PP
+\fIEvent port backend\fR
+.IX Subsection "Event port backend"
+.PP
+The scalable event interface for Solaris is called \*(L"event
+ports\*(R". Unfortunately, this mechanism is very buggy in all major
+releases. If you run into high \s-1CPU\s0 usage, your program freezes or you get
+a large number of spurious wakeups, make sure you have all the relevant
+and latest kernel patches applied. No, I don't know which ones, but there
+are multiple ones to apply, and afterwards, event ports actually work
+great.
+.PP
+If you can't get it to work, you can try running the program by setting
+the environment variable \f(CW\*(C`LIBEV_FLAGS=3\*(C'\fR to only allow \f(CW\*(C`poll\*(C'\fR and
+\&\f(CW\*(C`select\*(C'\fR backends.
+.SS "\s-1AIX POLL BUG\s0"
+.IX Subsection "AIX POLL BUG"
+\&\s-1AIX\s0 unfortunately has a broken \f(CW\*(C`poll.h\*(C'\fR header. Libev works around
+this by trying to avoid the poll backend altogether (i.e. it's not even
+compiled in), which normally isn't a big problem as \f(CW\*(C`select\*(C'\fR works fine
+with large bitsets on \s-1AIX,\s0 and \s-1AIX\s0 is dead anyway.
+.SS "\s-1WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS\s0"
+.IX Subsection "WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS"
+\fIGeneral issues\fR
+.IX Subsection "General issues"
+.PP
+Win32 doesn't support any of the standards (e.g. \s-1POSIX\s0) that libev
+requires, and its I/O model is fundamentally incompatible with the \s-1POSIX\s0
+model. Libev still offers limited functionality on this platform in
+the form of the \f(CW\*(C`EVBACKEND_SELECT\*(C'\fR backend, and only supports socket
+descriptors. This only applies when using Win32 natively, not when using
+e.g. cygwin. Actually, it only applies to the microsofts own compilers,
+as every compiler comes with a slightly differently broken/incompatible
+environment.
+.PP
+Lifting these limitations would basically require the full
+re-implementation of the I/O system. If you are into this kind of thing,
+then note that glib does exactly that for you in a very portable way (note
+also that glib is the slowest event library known to man).
+.PP
+There is no supported compilation method available on windows except
+embedding it into other applications.
+.PP
+Sensible signal handling is officially unsupported by Microsoft \- libev
+tries its best, but under most conditions, signals will simply not work.
+.PP
+Not a libev limitation but worth mentioning: windows apparently doesn't
+accept large writes: instead of resulting in a partial write, windows will
+either accept everything or return \f(CW\*(C`ENOBUFS\*(C'\fR if the buffer is too large,
+so make sure you only write small amounts into your sockets (less than a
+megabyte seems safe, but this apparently depends on the amount of memory
+available).
+.PP
+Due to the many, low, and arbitrary limits on the win32 platform and
+the abysmal performance of winsockets, using a large number of sockets
+is not recommended (and not reasonable). If your program needs to use
+more than a hundred or so sockets, then likely it needs to use a totally
+different implementation for windows, as libev offers the \s-1POSIX\s0 readiness
+notification model, which cannot be implemented efficiently on windows
+(due to Microsoft monopoly games).
+.PP
+A typical way to use libev under windows is to embed it (see the embedding
+section for details) and use the following \fIevwrap.h\fR header file instead
+of \fIev.h\fR:
+.PP
+.Vb 2
+\& #define EV_STANDALONE /* keeps ev from requiring config.h */
+\& #define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
+\&
+\& #include "ev.h"
+.Ve
+.PP
+And compile the following \fIevwrap.c\fR file into your project (make sure
+you do \fInot\fR compile the \fIev.c\fR or any other embedded source files!):
+.PP
+.Vb 2
+\& #include "evwrap.h"
+\& #include "ev.c"
+.Ve
+.PP
+\fIThe winsocket \f(CI\*(C`select\*(C'\fI function\fR
+.IX Subsection "The winsocket select function"
+.PP
+The winsocket \f(CW\*(C`select\*(C'\fR function doesn't follow \s-1POSIX\s0 in that it
+requires socket \fIhandles\fR and not socket \fIfile descriptors\fR (it is
+also extremely buggy). This makes select very inefficient, and also
+requires a mapping from file descriptors to socket handles (the Microsoft
+C runtime provides the function \f(CW\*(C`_open_osfhandle\*(C'\fR for this). See the
+discussion of the \f(CW\*(C`EV_SELECT_USE_FD_SET\*(C'\fR, \f(CW\*(C`EV_SELECT_IS_WINSOCKET\*(C'\fR and
+\&\f(CW\*(C`EV_FD_TO_WIN32_HANDLE\*(C'\fR preprocessor symbols for more info.
+.PP
+The configuration for a \*(L"naked\*(R" win32 using the Microsoft runtime
+libraries and raw winsocket select is:
+.PP
+.Vb 2
+\& #define EV_USE_SELECT 1
+\& #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
+.Ve
+.PP
+Note that winsockets handling of fd sets is O(n), so you can easily get a
+complexity in the O(nX) range when using win32.
+.PP
+\fILimited number of file descriptors\fR
+.IX Subsection "Limited number of file descriptors"
+.PP
+Windows has numerous arbitrary (and low) limits on things.
+.PP
+Early versions of winsocket's select only supported waiting for a maximum
+of \f(CW64\fR handles (probably owning to the fact that all windows kernels
+can only wait for \f(CW64\fR things at the same time internally; Microsoft
+recommends spawning a chain of threads and wait for 63 handles and the
+previous thread in each. Sounds great!).
+.PP
+Newer versions support more handles, but you need to define \f(CW\*(C`FD_SETSIZE\*(C'\fR
+to some high number (e.g. \f(CW2048\fR) before compiling the winsocket select
+call (which might be in libev or elsewhere, for example, perl and many
+other interpreters do their own select emulation on windows).
+.PP
+Another limit is the number of file descriptors in the Microsoft runtime
+libraries, which by default is \f(CW64\fR (there must be a hidden \fI64\fR
+fetish or something like this inside Microsoft). You can increase this
+by calling \f(CW\*(C`_setmaxstdio\*(C'\fR, which can increase this limit to \f(CW2048\fR
+(another arbitrary limit), but is broken in many versions of the Microsoft
+runtime libraries. This might get you to about \f(CW512\fR or \f(CW2048\fR sockets
+(depending on windows version and/or the phase of the moon). To get more,
+you need to wrap all I/O functions and provide your own fd management, but
+the cost of calling select (O(nX)) will likely make this unworkable.
+.SS "\s-1PORTABILITY REQUIREMENTS\s0"
+.IX Subsection "PORTABILITY REQUIREMENTS"
+In addition to a working ISO-C implementation and of course the
+backend-specific APIs, libev relies on a few additional extensions:
+.ie n .IP """void (*)(ev_watcher_type *, int revents)"" must have compatible calling conventions regardless of ""ev_watcher_type *""." 4
+.el .IP "\f(CWvoid (*)(ev_watcher_type *, int revents)\fR must have compatible calling conventions regardless of \f(CWev_watcher_type *\fR." 4
+.IX Item "void (*)(ev_watcher_type *, int revents) must have compatible calling conventions regardless of ev_watcher_type *."
+Libev assumes not only that all watcher pointers have the same internal
+structure (guaranteed by \s-1POSIX\s0 but not by \s-1ISO C\s0 for example), but it also
+assumes that the same (machine) code can be used to call any watcher
+callback: The watcher callbacks have different type signatures, but libev
+calls them using an \f(CW\*(C`ev_watcher *\*(C'\fR internally.
+.IP "null pointers and integer zero are represented by 0 bytes" 4
+.IX Item "null pointers and integer zero are represented by 0 bytes"
+Libev uses \f(CW\*(C`memset\*(C'\fR to initialise structs and arrays to \f(CW0\fR bytes, and
+relies on this setting pointers and integers to null.
+.IP "pointer accesses must be thread-atomic" 4
+.IX Item "pointer accesses must be thread-atomic"
+Accessing a pointer value must be atomic, it must both be readable and
+writable in one piece \- this is the case on all current architectures.
+.ie n .IP """sig_atomic_t volatile"" must be thread-atomic as well" 4
+.el .IP "\f(CWsig_atomic_t volatile\fR must be thread-atomic as well" 4
+.IX Item "sig_atomic_t volatile must be thread-atomic as well"
+The type \f(CW\*(C`sig_atomic_t volatile\*(C'\fR (or whatever is defined as
+\&\f(CW\*(C`EV_ATOMIC_T\*(C'\fR) must be atomic with respect to accesses from different
+threads. This is not part of the specification for \f(CW\*(C`sig_atomic_t\*(C'\fR, but is
+believed to be sufficiently portable.
+.ie n .IP """sigprocmask"" must work in a threaded environment" 4
+.el .IP "\f(CWsigprocmask\fR must work in a threaded environment" 4
+.IX Item "sigprocmask must work in a threaded environment"
+Libev uses \f(CW\*(C`sigprocmask\*(C'\fR to temporarily block signals. This is not
+allowed in a threaded program (\f(CW\*(C`pthread_sigmask\*(C'\fR has to be used). Typical
+pthread implementations will either allow \f(CW\*(C`sigprocmask\*(C'\fR in the \*(L"main
+thread\*(R" or will block signals process-wide, both behaviours would
+be compatible with libev. Interaction between \f(CW\*(C`sigprocmask\*(C'\fR and
+\&\f(CW\*(C`pthread_sigmask\*(C'\fR could complicate things, however.
+.Sp
+The most portable way to handle signals is to block signals in all threads
+except the initial one, and run the signal handling loop in the initial
+thread as well.
+.ie n .IP """long"" must be large enough for common memory allocation sizes" 4
+.el .IP "\f(CWlong\fR must be large enough for common memory allocation sizes" 4
+.IX Item "long must be large enough for common memory allocation sizes"
+To improve portability and simplify its \s-1API,\s0 libev uses \f(CW\*(C`long\*(C'\fR internally
+instead of \f(CW\*(C`size_t\*(C'\fR when allocating its data structures. On non-POSIX
+systems (Microsoft...) this might be unexpectedly low, but is still at
+least 31 bits everywhere, which is enough for hundreds of millions of
+watchers.
+.ie n .IP """double"" must hold a time value in seconds with enough accuracy" 4
+.el .IP "\f(CWdouble\fR must hold a time value in seconds with enough accuracy" 4
+.IX Item "double must hold a time value in seconds with enough accuracy"
+The type \f(CW\*(C`double\*(C'\fR is used to represent timestamps. It is required to
+have at least 51 bits of mantissa (and 9 bits of exponent), which is
+good enough for at least into the year 4000 with millisecond accuracy
+(the design goal for libev). This requirement is overfulfilled by
+implementations using \s-1IEEE 754,\s0 which is basically all existing ones.
+.Sp
+With \s-1IEEE 754\s0 doubles, you get microsecond accuracy until at least the
+year 2255 (and millisecond accuracy till the year 287396 \- by then, libev
+is either obsolete or somebody patched it to use \f(CW\*(C`long double\*(C'\fR or
+something like that, just kidding).
+.PP
+If you know of other additional requirements drop me a note.
+.SH "ALGORITHMIC COMPLEXITIES"
+.IX Header "ALGORITHMIC COMPLEXITIES"
+In this section the complexities of (many of) the algorithms used inside
+libev will be documented. For complexity discussions about backends see
+the documentation for \f(CW\*(C`ev_default_init\*(C'\fR.
+.PP
+All of the following are about amortised time: If an array needs to be
+extended, libev needs to realloc and move the whole array, but this
+happens asymptotically rarer with higher number of elements, so O(1) might
+mean that libev does a lengthy realloc operation in rare cases, but on
+average it is much faster and asymptotically approaches constant time.
+.IP "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)" 4
+.IX Item "Starting and stopping timer/periodic watchers: O(log skipped_other_timers)"
+This means that, when you have a watcher that triggers in one hour and
+there are 100 watchers that would trigger before that, then inserting will
+have to skip roughly seven (\f(CW\*(C`ld 100\*(C'\fR) of these watchers.
+.IP "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)" 4
+.IX Item "Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)"
+That means that changing a timer costs less than removing/adding them,
+as only the relative motion in the event queue has to be paid for.
+.IP "Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)" 4
+.IX Item "Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)"
+These just add the watcher into an array or at the head of a list.
+.IP "Stopping check/prepare/idle/fork/async watchers: O(1)" 4
+.IX Item "Stopping check/prepare/idle/fork/async watchers: O(1)"
+.PD 0
+.IP "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % \s-1EV_PID_HASHSIZE\s0))" 4
+.IX Item "Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))"
+.PD
+These watchers are stored in lists, so they need to be walked to find the
+correct watcher to remove. The lists are usually short (you don't usually
+have many watchers waiting for the same fd or signal: one is typical, two
+is rare).
+.IP "Finding the next timer in each loop iteration: O(1)" 4
+.IX Item "Finding the next timer in each loop iteration: O(1)"
+By virtue of using a binary or 4\-heap, the next timer is always found at a
+fixed position in the storage array.
+.IP "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)" 4
+.IX Item "Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)"
+A change means an I/O watcher gets started or stopped, which requires
+libev to recalculate its status (and possibly tell the kernel, depending
+on backend and whether \f(CW\*(C`ev_io_set\*(C'\fR was used).
+.IP "Activating one watcher (putting it into the pending state): O(1)" 4
+.IX Item "Activating one watcher (putting it into the pending state): O(1)"
+.PD 0
+.IP "Priority handling: O(number_of_priorities)" 4
+.IX Item "Priority handling: O(number_of_priorities)"
+.PD
+Priorities are implemented by allocating some space for each
+priority. When doing priority-based operations, libev usually has to
+linearly search all the priorities, but starting/stopping and activating
+watchers becomes O(1) with respect to priority handling.
+.IP "Sending an ev_async: O(1)" 4
+.IX Item "Sending an ev_async: O(1)"
+.PD 0
+.IP "Processing ev_async_send: O(number_of_async_watchers)" 4
+.IX Item "Processing ev_async_send: O(number_of_async_watchers)"
+.IP "Processing signals: O(max_signal_number)" 4
+.IX Item "Processing signals: O(max_signal_number)"
+.PD
+Sending involves a system call \fIiff\fR there were no other \f(CW\*(C`ev_async_send\*(C'\fR
+calls in the current loop iteration and the loop is currently
+blocked. Checking for async and signal events involves iterating over all
+running async watchers or all signal numbers.
+.SH "PORTING FROM LIBEV 3.X TO 4.X"
+.IX Header "PORTING FROM LIBEV 3.X TO 4.X"
+The major version 4 introduced some incompatible changes to the \s-1API.\s0
+.PP
+At the moment, the \f(CW\*(C`ev.h\*(C'\fR header file provides compatibility definitions
+for all changes, so most programs should still compile. The compatibility
+layer might be removed in later versions of libev, so better update to the
+new \s-1API\s0 early than late.
+.ie n .IP """EV_COMPAT3"" backwards compatibility mechanism" 4
+.el .IP "\f(CWEV_COMPAT3\fR backwards compatibility mechanism" 4
+.IX Item "EV_COMPAT3 backwards compatibility mechanism"
+The backward compatibility mechanism can be controlled by
+\&\f(CW\*(C`EV_COMPAT3\*(C'\fR. See \*(L"\s-1PREPROCESSOR SYMBOLS/MACROS\*(R"\s0 in the \*(L"\s-1EMBEDDING\*(R"\s0
+section.
+.ie n .IP """ev_default_destroy"" and ""ev_default_fork"" have been removed" 4
+.el .IP "\f(CWev_default_destroy\fR and \f(CWev_default_fork\fR have been removed" 4
+.IX Item "ev_default_destroy and ev_default_fork have been removed"
+These calls can be replaced easily by their \f(CW\*(C`ev_loop_xxx\*(C'\fR counterparts:
+.Sp
+.Vb 2
+\& ev_loop_destroy (EV_DEFAULT_UC);
+\& ev_loop_fork (EV_DEFAULT);
+.Ve
+.IP "function/symbol renames" 4
+.IX Item "function/symbol renames"
+A number of functions and symbols have been renamed:
+.Sp
+.Vb 3
+\& ev_loop => ev_run
+\& EVLOOP_NONBLOCK => EVRUN_NOWAIT
+\& EVLOOP_ONESHOT => EVRUN_ONCE
+\&
+\& ev_unloop => ev_break
+\& EVUNLOOP_CANCEL => EVBREAK_CANCEL
+\& EVUNLOOP_ONE => EVBREAK_ONE
+\& EVUNLOOP_ALL => EVBREAK_ALL
+\&
+\& EV_TIMEOUT => EV_TIMER
+\&
+\& ev_loop_count => ev_iteration
+\& ev_loop_depth => ev_depth
+\& ev_loop_verify => ev_verify
+.Ve
+.Sp
+Most functions working on \f(CW\*(C`struct ev_loop\*(C'\fR objects don't have an
+\&\f(CW\*(C`ev_loop_\*(C'\fR prefix, so it was removed; \f(CW\*(C`ev_loop\*(C'\fR, \f(CW\*(C`ev_unloop\*(C'\fR and
+associated constants have been renamed to not collide with the \f(CW\*(C`struct
+ev_loop\*(C'\fR anymore and \f(CW\*(C`EV_TIMER\*(C'\fR now follows the same naming scheme
+as all other watcher types. Note that \f(CW\*(C`ev_loop_fork\*(C'\fR is still called
+\&\f(CW\*(C`ev_loop_fork\*(C'\fR because it would otherwise clash with the \f(CW\*(C`ev_fork\*(C'\fR
+typedef.
+.ie n .IP """EV_MINIMAL"" mechanism replaced by ""EV_FEATURES""" 4
+.el .IP "\f(CWEV_MINIMAL\fR mechanism replaced by \f(CWEV_FEATURES\fR" 4
+.IX Item "EV_MINIMAL mechanism replaced by EV_FEATURES"
+The preprocessor symbol \f(CW\*(C`EV_MINIMAL\*(C'\fR has been replaced by a different
+mechanism, \f(CW\*(C`EV_FEATURES\*(C'\fR. Programs using \f(CW\*(C`EV_MINIMAL\*(C'\fR usually compile
+and work, but the library code will of course be larger.
+.SH "GLOSSARY"
+.IX Header "GLOSSARY"
+.IP "active" 4
+.IX Item "active"
+A watcher is active as long as it has been started and not yet stopped.
+See \*(L"\s-1WATCHER STATES\*(R"\s0 for details.
+.IP "application" 4
+.IX Item "application"
+In this document, an application is whatever is using libev.
+.IP "backend" 4
+.IX Item "backend"
+The part of the code dealing with the operating system interfaces.
+.IP "callback" 4
+.IX Item "callback"
+The address of a function that is called when some event has been
+detected. Callbacks are being passed the event loop, the watcher that
+received the event, and the actual event bitset.
+.IP "callback/watcher invocation" 4
+.IX Item "callback/watcher invocation"
+The act of calling the callback associated with a watcher.
+.IP "event" 4
+.IX Item "event"
+A change of state of some external event, such as data now being available
+for reading on a file descriptor, time having passed or simply not having
+any other events happening anymore.
+.Sp
+In libev, events are represented as single bits (such as \f(CW\*(C`EV_READ\*(C'\fR or
+\&\f(CW\*(C`EV_TIMER\*(C'\fR).
+.IP "event library" 4
+.IX Item "event library"
+A software package implementing an event model and loop.
+.IP "event loop" 4
+.IX Item "event loop"
+An entity that handles and processes external events and converts them
+into callback invocations.
+.IP "event model" 4
+.IX Item "event model"
+The model used to describe how an event loop handles and processes
+watchers and events.
+.IP "pending" 4
+.IX Item "pending"
+A watcher is pending as soon as the corresponding event has been
+detected. See \*(L"\s-1WATCHER STATES\*(R"\s0 for details.
+.IP "real time" 4
+.IX Item "real time"
+The physical time that is observed. It is apparently strictly monotonic :)
+.IP "wall-clock time" 4
+.IX Item "wall-clock time"
+The time and date as shown on clocks. Unlike real time, it can actually
+be wrong and jump forwards and backwards, e.g. when you adjust your
+clock.
+.IP "watcher" 4
+.IX Item "watcher"
+A data structure that describes interest in certain events. Watchers need
+to be started (attached to an event loop) before they can receive events.
+.SH "AUTHOR"
+.IX Header "AUTHOR"
+Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
+Magnusson and Emanuele Giaquinta, and minor corrections by many others.
--- rxvt-unicode/libev/ev.c
+++ rxvt-unicode/libev/ev.c
@@ -365,7 +365,7 @@
# define EV_HEAP_CACHE_AT EV_FEATURE_DATA
#endif
-#ifdef ANDROID
+#ifdef __ANDROID__
/* supposedly, android doesn't typedef fd_mask */
# undef EV_USE_SELECT
# define EV_USE_SELECT 0
@@ -1529,7 +1529,7 @@
#if EV_FEATURE_CODE
# define inline_speed ecb_inline
#else
-# define inline_speed static noinline
+# define inline_speed noinline static
#endif
#define NUMPRI (EV_MAXPRI - EV_MINPRI + 1)
@@ -1586,7 +1586,8 @@
#include <float.h>
/* a floor() replacement function, should be independent of ev_tstamp type */
-static ev_tstamp noinline
+noinline
+static ev_tstamp
ev_floor (ev_tstamp v)
{
/* the choice of shift factor is not terribly important */
@@ -1628,7 +1629,8 @@
# include <sys/utsname.h>
#endif
-static unsigned int noinline ecb_cold
+noinline ecb_cold
+static unsigned int
ev_linux_version (void)
{
#ifdef __linux
@@ -1667,7 +1669,8 @@
/*****************************************************************************/
#if EV_AVOID_STDIO
-static void noinline ecb_cold
+noinline ecb_cold
+static void
ev_printerr (const char *msg)
{
write (STDERR_FILENO, msg, strlen (msg));
@@ -1676,13 +1679,15 @@
static void (*syserr_cb)(const char *msg) EV_THROW;
-void ecb_cold
+ecb_cold
+void
ev_set_syserr_cb (void (*cb)(const char *msg) EV_THROW) EV_THROW
{
syserr_cb = cb;
}
-static void noinline ecb_cold
+noinline ecb_cold
+static void
ev_syserr (const char *msg)
{
if (!msg)
@@ -1723,7 +1728,8 @@
static void *(*alloc)(void *ptr, long size) EV_THROW = ev_realloc_emul;
-void ecb_cold
+ecb_cold
+void
ev_set_allocator (void *(*cb)(void *ptr, long size) EV_THROW) EV_THROW
{
alloc = cb;
@@ -1942,7 +1948,8 @@
return ncur;
}
-static void * noinline ecb_cold
+noinline ecb_cold
+static void *
array_realloc (int elem, void *base, int *cur, int cnt)
{
*cur = array_nextsize (elem, *cur, cnt);
@@ -1955,7 +1962,7 @@
#define array_needsize(type,base,cur,cnt,init) \
if (expect_false ((cnt) > (cur))) \
{ \
- int ecb_unused ocur_ = (cur); \
+ ecb_unused int ocur_ = (cur); \
(base) = (type *)array_realloc \
(sizeof (type), (base), &(cur), (cnt)); \
init ((base) + (ocur_), (cur) - ocur_); \
@@ -1977,12 +1984,14 @@
/*****************************************************************************/
/* dummy callback for pending events */
-static void noinline
+noinline
+static void
pendingcb (EV_P_ ev_prepare *w, int revents)
{
}
-void noinline
+noinline
+void
ev_feed_event (EV_P_ void *w, int revents) EV_THROW
{
W w_ = (W)w;
@@ -2122,7 +2131,8 @@
}
/* something about the given fd changed */
-inline_size void
+inline_size
+void
fd_change (EV_P_ int fd, int flags)
{
unsigned char reify = anfds [fd].reify;
@@ -2137,7 +2147,7 @@
}
/* the given fd is invalid/unusable, so make sure it doesn't hurt us anymore */
-inline_speed void ecb_cold
+inline_speed ecb_cold void
fd_kill (EV_P_ int fd)
{
ev_io *w;
@@ -2150,7 +2160,7 @@
}
/* check whether the given fd is actually valid, for error recovery */
-inline_size int ecb_cold
+inline_size ecb_cold int
fd_valid (int fd)
{
#ifdef _WIN32
@@ -2161,7 +2171,8 @@
}
/* called on EBADF to verify fds */
-static void noinline ecb_cold
+noinline ecb_cold
+static void
fd_ebadf (EV_P)
{
int fd;
@@ -2173,7 +2184,8 @@
}
/* called on ENOMEM in select/poll to kill some fds and retry */
-static void noinline ecb_cold
+noinline ecb_cold
+static void
fd_enomem (EV_P)
{
int fd;
@@ -2187,7 +2199,8 @@
}
/* usually called after fork if backend needs to re-arm all fds from scratch */
-static void noinline
+noinline
+static void
fd_rearm_all (EV_P)
{
int fd;
@@ -2378,7 +2391,8 @@
#if EV_SIGNAL_ENABLE || EV_ASYNC_ENABLE
-static void noinline ecb_cold
+noinline ecb_cold
+static void
evpipe_init (EV_P)
{
if (!ev_is_active (&pipe_w))
@@ -2566,7 +2580,8 @@
ev_feed_signal (signum);
}
-void noinline
+noinline
+void
ev_feed_signal_event (EV_P_ int signum) EV_THROW
{
WL w;
@@ -2693,20 +2708,20 @@
# include "ev_select.c"
#endif
-int ecb_cold
+ecb_cold int
ev_version_major (void) EV_THROW
{
return EV_VERSION_MAJOR;
}
-int ecb_cold
+ecb_cold int
ev_version_minor (void) EV_THROW
{
return EV_VERSION_MINOR;
}
/* return true if we are running with elevated privileges and should ignore env variables */
-int inline_size ecb_cold
+inline_size ecb_cold int
enable_secure (void)
{
#ifdef _WIN32
@@ -2717,7 +2732,8 @@
#endif
}
-unsigned int ecb_cold
+ecb_cold
+unsigned int
ev_supported_backends (void) EV_THROW
{
unsigned int flags = 0;
@@ -2731,7 +2747,8 @@
return flags;
}
-unsigned int ecb_cold
+ecb_cold
+unsigned int
ev_recommended_backends (void) EV_THROW
{
unsigned int flags = ev_supported_backends ();
@@ -2753,7 +2770,8 @@
return flags;
}
-unsigned int ecb_cold
+ecb_cold
+unsigned int
ev_embeddable_backends (void) EV_THROW
{
int flags = EVBACKEND_EPOLL | EVBACKEND_KQUEUE | EVBACKEND_PORT;
@@ -2823,7 +2841,8 @@
#endif
/* initialise a loop structure, must be zero-initialised */
-static void noinline ecb_cold
+noinline ecb_cold
+static void
loop_init (EV_P_ unsigned int flags) EV_THROW
{
if (!backend)
@@ -2920,7 +2939,8 @@
}
/* free up a loop structure */
-void ecb_cold
+ecb_cold
+void
ev_loop_destroy (EV_P)
{
int i;
@@ -3072,7 +3092,8 @@
#if EV_MULTIPLICITY
-struct ev_loop * ecb_cold
+ecb_cold
+struct ev_loop *
ev_loop_new (unsigned int flags) EV_THROW
{
EV_P = (struct ev_loop *)ev_malloc (sizeof (struct ev_loop));
@@ -3090,7 +3111,8 @@
#endif /* multiplicity */
#if EV_VERIFY
-static void noinline ecb_cold
+noinline ecb_cold
+static void
verify_watcher (EV_P_ W w)
{
assert (("libev: watcher has invalid priority", ABSPRI (w) >= 0 && ABSPRI (w) < NUMPRI));
@@ -3099,7 +3121,8 @@
assert (("libev: pending watcher not on pending queue", pendings [ABSPRI (w)][w->pending - 1].w == w));
}
-static void noinline ecb_cold
+noinline ecb_cold
+static void
verify_heap (EV_P_ ANHE *heap, int N)
{
int i;
@@ -3114,7 +3137,8 @@
}
}
-static void noinline ecb_cold
+noinline ecb_cold
+static void
array_verify (EV_P_ W *ws, int cnt)
{
while (cnt--)
@@ -3213,7 +3237,8 @@
#endif
#if EV_MULTIPLICITY
-struct ev_loop * ecb_cold
+ecb_cold
+struct ev_loop *
#else
int
#endif
@@ -3271,7 +3296,8 @@
return count;
}
-void noinline
+noinline
+void
ev_invoke_pending (EV_P)
{
pendingpri = NUMPRI;
@@ -3356,7 +3382,8 @@
#if EV_PERIODIC_ENABLE
-static void noinline
+noinline
+static void
periodic_recalc (EV_P_ ev_periodic *w)
{
ev_tstamp interval = w->interval > MIN_INTERVAL ? w->interval : MIN_INTERVAL;
@@ -3424,7 +3451,8 @@
/* simply recalculate all periodics */
/* TODO: maybe ensure that at least one event happens when jumping forward? */
-static void noinline ecb_cold
+noinline ecb_cold
+static void
periodics_reschedule (EV_P)
{
int i;
@@ -3447,7 +3475,8 @@
#endif
/* adjust all timers by a given offset */
-static void noinline ecb_cold
+noinline ecb_cold
+static void
timers_reschedule (EV_P_ ev_tstamp adjust)
{
int i;
@@ -3825,7 +3854,8 @@
/*****************************************************************************/
-void noinline
+noinline
+void
ev_io_start (EV_P_ ev_io *w) EV_THROW
{
int fd = w->fd;
@@ -3851,7 +3881,8 @@
EV_FREQUENT_CHECK;
}
-void noinline
+noinline
+void
ev_io_stop (EV_P_ ev_io *w) EV_THROW
{
clear_pending (EV_A_ (W)w);
@@ -3870,7 +3901,8 @@
EV_FREQUENT_CHECK;
}
-void noinline
+noinline
+void
ev_timer_start (EV_P_ ev_timer *w) EV_THROW
{
if (expect_false (ev_is_active (w)))
@@ -3894,7 +3926,8 @@
/*assert (("libev: internal timer heap corruption", timers [ev_active (w)] == (WT)w));*/
}
-void noinline
+noinline
+void
ev_timer_stop (EV_P_ ev_timer *w) EV_THROW
{
clear_pending (EV_A_ (W)w);
@@ -3924,7 +3957,8 @@
EV_FREQUENT_CHECK;
}
-void noinline
+noinline
+void
ev_timer_again (EV_P_ ev_timer *w) EV_THROW
{
EV_FREQUENT_CHECK;
@@ -3958,7 +3992,8 @@
}
#if EV_PERIODIC_ENABLE
-void noinline
+noinline
+void
ev_periodic_start (EV_P_ ev_periodic *w) EV_THROW
{
if (expect_false (ev_is_active (w)))
@@ -3988,7 +4023,8 @@
/*assert (("libev: internal periodic heap corruption", ANHE_w (periodics [ev_active (w)]) == (WT)w));*/
}
-void noinline
+noinline
+void
ev_periodic_stop (EV_P_ ev_periodic *w) EV_THROW
{
clear_pending (EV_A_ (W)w);
@@ -4016,7 +4052,8 @@
EV_FREQUENT_CHECK;
}
-void noinline
+noinline
+void
ev_periodic_again (EV_P_ ev_periodic *w) EV_THROW
{
/* TODO: use adjustheap and recalculation */
@@ -4031,7 +4068,8 @@
#if EV_SIGNAL_ENABLE
-void noinline
+noinline
+void
ev_signal_start (EV_P_ ev_signal *w) EV_THROW
{
if (expect_false (ev_is_active (w)))
@@ -4113,7 +4151,8 @@
EV_FREQUENT_CHECK;
}
-void noinline
+noinline
+void
ev_signal_stop (EV_P_ ev_signal *w) EV_THROW
{
clear_pending (EV_A_ (W)w);
@@ -4199,14 +4238,15 @@
#define NFS_STAT_INTERVAL 30.1074891 /* for filesystems potentially failing inotify */
#define MIN_STAT_INTERVAL 0.1074891
-static void noinline stat_timer_cb (EV_P_ ev_timer *w_, int revents);
+noinline static void stat_timer_cb (EV_P_ ev_timer *w_, int revents);
#if EV_USE_INOTIFY
/* the * 2 is to allow for alignment padding, which for some reason is >> 8 */
# define EV_INOTIFY_BUFSIZE (sizeof (struct inotify_event) * 2 + NAME_MAX)
-static void noinline
+noinline
+static void
infy_add (EV_P_ ev_stat *w)
{
w->wd = inotify_add_watch (fs_fd, w->path,
@@ -4280,7 +4320,8 @@
if (ev_is_active (&w->timer)) ev_unref (EV_A);
}
-static void noinline
+noinline
+static void
infy_del (EV_P_ ev_stat *w)
{
int slot;
@@ -4297,7 +4338,8 @@
inotify_rm_watch (fs_fd, wd);
}
-static void noinline
+noinline
+static void
infy_wd (EV_P_ int slot, int wd, struct inotify_event *ev)
{
if (slot < 0)
@@ -4343,7 +4385,8 @@
}
}
-inline_size void ecb_cold
+inline_size ecb_cold
+void
ev_check_2625 (EV_P)
{
/* kernels < 2.6.25 are borked
@@ -4451,7 +4494,8 @@
w->attr.st_nlink = 1;
}
-static void noinline
+noinline
+static void
stat_timer_cb (EV_P_ ev_timer *w_, int revents)
{
ev_stat *w = (ev_stat *)(((char *)w_) - offsetof (ev_stat, timer));
@@ -4671,7 +4715,8 @@
#endif
#if EV_EMBED_ENABLE
-void noinline
+noinline
+void
ev_embed_sweep (EV_P_ ev_embed *w) EV_THROW
{
ev_run (w->other, EVRUN_NOWAIT);
@@ -4978,7 +5023,8 @@
/*****************************************************************************/
#if EV_WALK_ENABLE
-void ecb_cold
+ecb_cold
+void
ev_walk (EV_P_ int types, void (*cb)(EV_P_ int type, void *w)) EV_THROW
{
int i, j;
--- rxvt-unicode/libev/event.c
+++ rxvt-unicode/libev/event.c
@@ -0,0 +1,425 @@
+/*
+ * libevent compatibility layer
+ *
+ * Copyright (c) 2007,2008,2009,2010,2012 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#include <stddef.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#ifdef EV_EVENT_H
+# include EV_EVENT_H
+#else
+# include "event.h"
+#endif
+
+#if EV_MULTIPLICITY
+# define dLOOPev struct ev_loop *loop = (struct ev_loop *)ev->ev_base
+# define dLOOPbase struct ev_loop *loop = (struct ev_loop *)base
+#else
+# define dLOOPev
+# define dLOOPbase
+#endif
+
+/* never accessed, will always be cast from/to ev_loop */
+struct event_base
+{
+ int dummy;
+};
+
+static struct event_base *ev_x_cur;
+
+static ev_tstamp
+ev_tv_get (struct timeval *tv)
+{
+ if (tv)
+ {
+ ev_tstamp after = tv->tv_sec + tv->tv_usec * 1e-6;
+ return after ? after : 1e-6;
+ }
+ else
+ return -1.;
+}
+
+#define EVENT_STRINGIFY(s) # s
+#define EVENT_VERSION(a,b) EVENT_STRINGIFY (a) "." EVENT_STRINGIFY (b)
+
+const char *
+event_get_version (void)
+{
+ /* returns ABI, not API or library, version */
+ return EVENT_VERSION (EV_VERSION_MAJOR, EV_VERSION_MINOR);
+}
+
+const char *
+event_get_method (void)
+{
+ return "libev";
+}
+
+void *event_init (void)
+{
+#if EV_MULTIPLICITY
+ if (ev_x_cur)
+ ev_x_cur = (struct event_base *)ev_loop_new (EVFLAG_AUTO);
+ else
+ ev_x_cur = (struct event_base *)ev_default_loop (EVFLAG_AUTO);
+#else
+ assert (("libev: multiple event bases not supported when not compiled with EV_MULTIPLICITY", !ev_x_cur));
+
+ ev_x_cur = (struct event_base *)(long)ev_default_loop (EVFLAG_AUTO);
+#endif
+
+ return ev_x_cur;
+}
+
+const char *
+event_base_get_method (const struct event_base *base)
+{
+ return "libev";
+}
+
+struct event_base *
+event_base_new (void)
+{
+#if EV_MULTIPLICITY
+ return (struct event_base *)ev_loop_new (EVFLAG_AUTO);
+#else
+ assert (("libev: multiple event bases not supported when not compiled with EV_MULTIPLICITY"));
+ return NULL;
+#endif
+}
+
+void event_base_free (struct event_base *base)
+{
+ dLOOPbase;
+
+#if EV_MULTIPLICITY
+ if (!ev_is_default_loop (loop))
+ ev_loop_destroy (loop);
+#endif
+}
+
+int event_dispatch (void)
+{
+ return event_base_dispatch (ev_x_cur);
+}
+
+#ifdef EV_STANDALONE
+void event_set_log_callback (event_log_cb cb)
+{
+ /* nop */
+}
+#endif
+
+int event_loop (int flags)
+{
+ return event_base_loop (ev_x_cur, flags);
+}
+
+int event_loopexit (struct timeval *tv)
+{
+ return event_base_loopexit (ev_x_cur, tv);
+}
+
+event_callback_fn event_get_callback
+(const struct event *ev)
+{
+ return ev->ev_callback;
+}
+
+static void
+ev_x_cb (struct event *ev, int revents)
+{
+ revents &= EV_READ | EV_WRITE | EV_TIMER | EV_SIGNAL;
+
+ ev->ev_res = revents;
+ ev->ev_callback (ev->ev_fd, (short)revents, ev->ev_arg);
+}
+
+static void
+ev_x_cb_sig (EV_P_ struct ev_signal *w, int revents)
+{
+ struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, iosig.sig));
+
+ if (revents & EV_ERROR)
+ event_del (ev);
+
+ ev_x_cb (ev, revents);
+}
+
+static void
+ev_x_cb_io (EV_P_ struct ev_io *w, int revents)
+{
+ struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, iosig.io));
+
+ if ((revents & EV_ERROR) || !(ev->ev_events & EV_PERSIST))
+ event_del (ev);
+
+ ev_x_cb (ev, revents);
+}
+
+static void
+ev_x_cb_to (EV_P_ struct ev_timer *w, int revents)
+{
+ struct event *ev = (struct event *)(((char *)w) - offsetof (struct event, to));
+
+ event_del (ev);
+
+ ev_x_cb (ev, revents);
+}
+
+void event_set (struct event *ev, int fd, short events, void (*cb)(int, short, void *), void *arg)
+{
+ if (events & EV_SIGNAL)
+ ev_init (&ev->iosig.sig, ev_x_cb_sig);
+ else
+ ev_init (&ev->iosig.io, ev_x_cb_io);
+
+ ev_init (&ev->to, ev_x_cb_to);
+
+ ev->ev_base = ev_x_cur; /* not threadsafe, but it's how libevent works */
+ ev->ev_fd = fd;
+ ev->ev_events = events;
+ ev->ev_pri = 0;
+ ev->ev_callback = cb;
+ ev->ev_arg = arg;
+ ev->ev_res = 0;
+ ev->ev_flags = EVLIST_INIT;
+}
+
+int event_once (int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv)
+{
+ return event_base_once (ev_x_cur, fd, events, cb, arg, tv);
+}
+
+int event_add (struct event *ev, struct timeval *tv)
+{
+ dLOOPev;
+
+ if (ev->ev_events & EV_SIGNAL)
+ {
+ if (!ev_is_active (&ev->iosig.sig))
+ {
+ ev_signal_set (&ev->iosig.sig, ev->ev_fd);
+ ev_signal_start (EV_A_ &ev->iosig.sig);
+
+ ev->ev_flags |= EVLIST_SIGNAL;
+ }
+ }
+ else if (ev->ev_events & (EV_READ | EV_WRITE))
+ {
+ if (!ev_is_active (&ev->iosig.io))
+ {
+ ev_io_set (&ev->iosig.io, ev->ev_fd, ev->ev_events & (EV_READ | EV_WRITE));
+ ev_io_start (EV_A_ &ev->iosig.io);
+
+ ev->ev_flags |= EVLIST_INSERTED;
+ }
+ }
+
+ if (tv)
+ {
+ ev->to.repeat = ev_tv_get (tv);
+ ev_timer_again (EV_A_ &ev->to);
+ ev->ev_flags |= EVLIST_TIMEOUT;
+ }
+ else
+ {
+ ev_timer_stop (EV_A_ &ev->to);
+ ev->ev_flags &= ~EVLIST_TIMEOUT;
+ }
+
+ ev->ev_flags |= EVLIST_ACTIVE;
+
+ return 0;
+}
+
+int event_del (struct event *ev)
+{
+ dLOOPev;
+
+ if (ev->ev_events & EV_SIGNAL)
+ ev_signal_stop (EV_A_ &ev->iosig.sig);
+ else if (ev->ev_events & (EV_READ | EV_WRITE))
+ ev_io_stop (EV_A_ &ev->iosig.io);
+
+ if (ev_is_active (&ev->to))
+ ev_timer_stop (EV_A_ &ev->to);
+
+ ev->ev_flags = EVLIST_INIT;
+
+ return 0;
+}
+
+void event_active (struct event *ev, int res, short ncalls)
+{
+ dLOOPev;
+
+ if (res & EV_TIMEOUT)
+ ev_feed_event (EV_A_ &ev->to, res & EV_TIMEOUT);
+
+ if (res & EV_SIGNAL)
+ ev_feed_event (EV_A_ &ev->iosig.sig, res & EV_SIGNAL);
+
+ if (res & (EV_READ | EV_WRITE))
+ ev_feed_event (EV_A_ &ev->iosig.io, res & (EV_READ | EV_WRITE));
+}
+
+int event_pending (struct event *ev, short events, struct timeval *tv)
+{
+ short revents = 0;
+ dLOOPev;
+
+ if (ev->ev_events & EV_SIGNAL)
+ {
+ /* sig */
+ if (ev_is_active (&ev->iosig.sig) || ev_is_pending (&ev->iosig.sig))
+ revents |= EV_SIGNAL;
+ }
+ else if (ev->ev_events & (EV_READ | EV_WRITE))
+ {
+ /* io */
+ if (ev_is_active (&ev->iosig.io) || ev_is_pending (&ev->iosig.io))
+ revents |= ev->ev_events & (EV_READ | EV_WRITE);
+ }
+
+ if (ev->ev_events & EV_TIMEOUT || ev_is_active (&ev->to) || ev_is_pending (&ev->to))
+ {
+ revents |= EV_TIMEOUT;
+
+ if (tv)
+ {
+ ev_tstamp at = ev_now (EV_A);
+
+ tv->tv_sec = (long)at;
+ tv->tv_usec = (long)((at - (ev_tstamp)tv->tv_sec) * 1e6);
+ }
+ }
+
+ return events & revents;
+}
+
+int event_priority_init (int npri)
+{
+ return event_base_priority_init (ev_x_cur, npri);
+}
+
+int event_priority_set (struct event *ev, int pri)
+{
+ ev->ev_pri = pri;
+
+ return 0;
+}
+
+int event_base_set (struct event_base *base, struct event *ev)
+{
+ ev->ev_base = base;
+
+ return 0;
+}
+
+int event_base_loop (struct event_base *base, int flags)
+{
+ dLOOPbase;
+
+ return !ev_run (EV_A_ flags);
+}
+
+int event_base_dispatch (struct event_base *base)
+{
+ return event_base_loop (base, 0);
+}
+
+static void
+ev_x_loopexit_cb (int revents, void *base)
+{
+ dLOOPbase;
+
+ ev_break (EV_A_ EVBREAK_ONE);
+}
+
+int event_base_loopexit (struct event_base *base, struct timeval *tv)
+{
+ ev_tstamp after = ev_tv_get (tv);
+ dLOOPbase;
+
+ ev_once (EV_A_ -1, 0, after >= 0. ? after : 0., ev_x_loopexit_cb, (void *)base);
+
+ return 0;
+}
+
+struct ev_x_once
+{
+ int fd;
+ void (*cb)(int, short, void *);
+ void *arg;
+};
+
+static void
+ev_x_once_cb (int revents, void *arg)
+{
+ struct ev_x_once *once = (struct ev_x_once *)arg;
+
+ once->cb (once->fd, (short)revents, once->arg);
+ free (once);
+}
+
+int event_base_once (struct event_base *base, int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv)
+{
+ struct ev_x_once *once = (struct ev_x_once *)malloc (sizeof (struct ev_x_once));
+ dLOOPbase;
+
+ if (!once)
+ return -1;
+
+ once->fd = fd;
+ once->cb = cb;
+ once->arg = arg;
+
+ ev_once (EV_A_ fd, events & (EV_READ | EV_WRITE), ev_tv_get (tv), ev_x_once_cb, (void *)once);
+
+ return 0;
+}
+
+int event_base_priority_init (struct event_base *base, int npri)
+{
+ /*dLOOPbase;*/
+
+ return 0;
+}
+
--- rxvt-unicode/libev/event_compat.h
+++ rxvt-unicode/libev/event_compat.h
@@ -0,0 +1,226 @@
+/*
+ * Copyright (c) 2000-2004 Niels Provos <provos@citi.umich.edu>
+ * Copyright (c) 2008 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifdef _WIN32
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+# undef WIN32_LEAN_AND_MEAN
+typedef unsigned char u_char;
+typedef unsigned short u_short;
+#else
+# include <sys/types.h>
+# include <sys/time.h>
+# include <inttypes.h>
+#endif
+
+#include <stdarg.h>
+
+/* Fix so that ppl dont have to run with <sys/queue.h> */
+#ifndef TAILQ_ENTRY
+#define _EVENT_DEFINED_TQENTRY
+#define TAILQ_ENTRY(type) \
+struct { \
+ struct type *tqe_next; /* next element */ \
+ struct type **tqe_prev; /* address of previous next element */ \
+}
+#endif /* !TAILQ_ENTRY */
+#ifndef RB_ENTRY
+#define _EVENT_DEFINED_RBENTRY
+#define RB_ENTRY(type) \
+struct { \
+ struct type *rbe_left; /* left element */ \
+ struct type *rbe_right; /* right element */ \
+ struct type *rbe_parent; /* parent element */ \
+ int rbe_color; /* node color */ \
+}
+#endif /* !RB_ENTRY */
+
+/*
+ * Key-Value pairs. Can be used for HTTP headers but also for
+ * query argument parsing.
+ */
+struct evkeyval {
+ TAILQ_ENTRY(evkeyval) next;
+
+ char *key;
+ char *value;
+};
+
+#ifdef _EVENT_DEFINED_TQENTRY
+#undef TAILQ_ENTRY
+struct event_list;
+struct evkeyvalq;
+#undef _EVENT_DEFINED_TQENTRY
+#else
+TAILQ_HEAD (event_list, event);
+TAILQ_HEAD (evkeyvalq, evkeyval);
+#endif /* _EVENT_DEFINED_TQENTRY */
+#ifdef _EVENT_DEFINED_RBENTRY
+#undef RB_ENTRY
+#undef _EVENT_DEFINED_RBENTRY
+#endif /* _EVENT_DEFINED_RBENTRY */
+
+struct eventop {
+ char *name;
+ void *(*init)(struct event_base *);
+ int (*add)(void *, struct event *);
+ int (*del)(void *, struct event *);
+ int (*recalc)(struct event_base *, void *, int);
+ int (*dispatch)(struct event_base *, void *, struct timeval *);
+ void (*dealloc)(struct event_base *, void *);
+};
+
+/* These functions deal with buffering input and output */
+
+struct evbuffer {
+ u_char *buffer;
+ u_char *orig_buffer;
+
+ size_t misalign;
+ size_t totallen;
+ size_t off;
+
+ void (*cb)(struct evbuffer *, size_t, size_t, void *);
+ void *cbarg;
+};
+
+/* Just for error reporting - use other constants otherwise */
+#define EVBUFFER_READ 0x01
+#define EVBUFFER_WRITE 0x02
+#define EVBUFFER_EOF 0x10
+#define EVBUFFER_ERROR 0x20
+#define EVBUFFER_TIMEOUT 0x40
+
+struct bufferevent;
+typedef void (*evbuffercb)(struct bufferevent *, void *);
+typedef void (*everrorcb)(struct bufferevent *, short what, void *);
+
+struct event_watermark {
+ size_t low;
+ size_t high;
+};
+
+struct bufferevent {
+ struct event ev_read;
+ struct event ev_write;
+
+ struct evbuffer *input;
+ struct evbuffer *output;
+
+ struct event_watermark wm_read;
+ struct event_watermark wm_write;
+
+ evbuffercb readcb;
+ evbuffercb writecb;
+ everrorcb errorcb;
+ void *cbarg;
+
+ int timeout_read; /* in seconds */
+ int timeout_write; /* in seconds */
+
+ short enabled; /* events that are currently enabled */
+};
+
+struct bufferevent *bufferevent_new(int fd,
+ evbuffercb readcb, evbuffercb writecb, everrorcb errorcb, void *cbarg);
+int bufferevent_base_set(struct event_base *base, struct bufferevent *bufev);
+int bufferevent_priority_set(struct bufferevent *bufev, int pri);
+void bufferevent_free(struct bufferevent *bufev);
+int bufferevent_write(struct bufferevent *bufev, const void *data, size_t size);
+int bufferevent_write_buffer(struct bufferevent *bufev, struct evbuffer *buf);
+size_t bufferevent_read(struct bufferevent *bufev, void *data, size_t size);
+int bufferevent_enable(struct bufferevent *bufev, short event);
+int bufferevent_disable(struct bufferevent *bufev, short event);
+void bufferevent_settimeout(struct bufferevent *bufev,
+ int timeout_read, int timeout_write);
+
+#define EVBUFFER_LENGTH(x) (x)->off
+#define EVBUFFER_DATA(x) (x)->buffer
+#define EVBUFFER_INPUT(x) (x)->input
+#define EVBUFFER_OUTPUT(x) (x)->output
+
+struct evbuffer *evbuffer_new(void);
+void evbuffer_free(struct evbuffer *);
+int evbuffer_expand(struct evbuffer *, size_t);
+int evbuffer_add(struct evbuffer *, const void *, size_t);
+int evbuffer_remove(struct evbuffer *, void *, size_t);
+char *evbuffer_readline(struct evbuffer *);
+int evbuffer_add_buffer(struct evbuffer *, struct evbuffer *);
+int evbuffer_add_printf(struct evbuffer *, const char *fmt, ...);
+int evbuffer_add_vprintf(struct evbuffer *, const char *fmt, va_list ap);
+void evbuffer_drain(struct evbuffer *, size_t);
+int evbuffer_write(struct evbuffer *, int);
+int evbuffer_read(struct evbuffer *, int, int);
+u_char *evbuffer_find(struct evbuffer *, const u_char *, size_t);
+void evbuffer_setcb(struct evbuffer *, void (*)(struct evbuffer *, size_t, size_t, void *), void *);
+
+/*
+ * Marshaling tagged data - We assume that all tags are inserted in their
+ * numeric order - so that unknown tags will always be higher than the
+ * known ones - and we can just ignore the end of an event buffer.
+ */
+
+void evtag_init(void);
+
+void evtag_marshal(struct evbuffer *evbuf, uint32_t tag, const void *data,
+ uint32_t len);
+
+void encode_int(struct evbuffer *evbuf, uint32_t number);
+
+void evtag_marshal_int(struct evbuffer *evbuf, uint32_t tag, uint32_t integer);
+
+void evtag_marshal_string(struct evbuffer *buf, uint32_t tag,
+ const char *string);
+
+void evtag_marshal_timeval(struct evbuffer *evbuf, uint32_t tag,
+ struct timeval *tv);
+
+int evtag_unmarshal(struct evbuffer *src, uint32_t *ptag, struct evbuffer *dst);
+int evtag_peek(struct evbuffer *evbuf, uint32_t *ptag);
+int evtag_peek_length(struct evbuffer *evbuf, uint32_t *plength);
+int evtag_payload_length(struct evbuffer *evbuf, uint32_t *plength);
+int evtag_consume(struct evbuffer *evbuf);
+
+int evtag_unmarshal_int(struct evbuffer *evbuf, uint32_t need_tag,
+ uint32_t *pinteger);
+
+int evtag_unmarshal_fixed(struct evbuffer *src, uint32_t need_tag, void *data,
+ size_t len);
+
+int evtag_unmarshal_string(struct evbuffer *evbuf, uint32_t need_tag,
+ char **pstring);
+
+int evtag_unmarshal_timeval(struct evbuffer *evbuf, uint32_t need_tag,
+ struct timeval *ptv);
+
+#ifdef __cplusplus
+}
+#endif
--- rxvt-unicode/libev/event.h
+++ rxvt-unicode/libev/event.h
@@ -0,0 +1,177 @@
+/*
+ * libevent compatibility header, only core events supported
+ *
+ * Copyright (c) 2007,2008,2010,2012 Marc Alexander Lehmann <libev@schmorp.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modifica-
+ * tion, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
+ * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
+ * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
+ * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * the GNU General Public License ("GPL") version 2 or any later version,
+ * in which case the provisions of the GPL are applicable instead of
+ * the above. If you wish to allow the use of your version of this file
+ * only under the terms of the GPL and not to allow others to use your
+ * version of this file under the BSD license, indicate your decision
+ * by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL. If you do not delete the
+ * provisions above, a recipient may use your version of this file under
+ * either the BSD or the GPL.
+ */
+
+#ifndef EVENT_H_
+#define EVENT_H_
+
+#ifdef EV_H
+# include EV_H
+#else
+# include "ev.h"
+#endif
+
+#ifndef EVLOOP_NONBLOCK
+# define EVLOOP_NONBLOCK EVRUN_NOWAIT
+#endif
+#ifndef EVLOOP_ONESHOT
+# define EVLOOP_ONESHOT EVRUN_ONCE
+#endif
+#ifndef EV_TIMEOUT
+# define EV_TIMEOUT EV_TIMER
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* we need sys/time.h for struct timeval only */
+#if !defined (WIN32) || defined (__MINGW32__)
+# include <time.h> /* mingw seems to need this, for whatever reason */
+# include <sys/time.h>
+#endif
+
+struct event_base;
+
+#define EVLIST_TIMEOUT 0x01
+#define EVLIST_INSERTED 0x02
+#define EVLIST_SIGNAL 0x04
+#define EVLIST_ACTIVE 0x08
+#define EVLIST_INTERNAL 0x10
+#define EVLIST_INIT 0x80
+
+typedef void (*event_callback_fn)(int, short, void *);
+
+struct event
+{
+ /* libev watchers we map onto */
+ union {
+ struct ev_io io;
+ struct ev_signal sig;
+ } iosig;
+ struct ev_timer to;
+
+ /* compatibility slots */
+ struct event_base *ev_base;
+ event_callback_fn ev_callback;
+ void *ev_arg;
+ int ev_fd;
+ int ev_pri;
+ int ev_res;
+ int ev_flags;
+ short ev_events;
+};
+
+event_callback_fn event_get_callback (const struct event *ev);
+
+#define EV_READ EV_READ
+#define EV_WRITE EV_WRITE
+#define EV_PERSIST 0x10
+#define EV_ET 0x20 /* nop */
+
+#define EVENT_SIGNAL(ev) ((int) (ev)->ev_fd)
+#define EVENT_FD(ev) ((int) (ev)->ev_fd)
+
+#define event_initialized(ev) ((ev)->ev_flags & EVLIST_INIT)
+
+#define evtimer_add(ev,tv) event_add (ev, tv)
+#define evtimer_set(ev,cb,data) event_set (ev, -1, 0, cb, data)
+#define evtimer_del(ev) event_del (ev)
+#define evtimer_pending(ev,tv) event_pending (ev, EV_TIMEOUT, tv)
+#define evtimer_initialized(ev) event_initialized (ev)
+
+#define timeout_add(ev,tv) evtimer_add (ev, tv)
+#define timeout_set(ev,cb,data) evtimer_set (ev, cb, data)
+#define timeout_del(ev) evtimer_del (ev)
+#define timeout_pending(ev,tv) evtimer_pending (ev, tv)
+#define timeout_initialized(ev) evtimer_initialized (ev)
+
+#define signal_add(ev,tv) event_add (ev, tv)
+#define signal_set(ev,sig,cb,data) event_set (ev, sig, EV_SIGNAL | EV_PERSIST, cb, data)
+#define signal_del(ev) event_del (ev)
+#define signal_pending(ev,tv) event_pending (ev, EV_SIGNAL, tv)
+#define signal_initialized(ev) event_initialized (ev)
+
+const char *event_get_version (void);
+const char *event_get_method (void);
+
+void *event_init (void);
+void event_base_free (struct event_base *base);
+
+#define EVLOOP_ONCE EVLOOP_ONESHOT
+int event_loop (int);
+int event_loopexit (struct timeval *tv);
+int event_dispatch (void);
+
+#define _EVENT_LOG_DEBUG 0
+#define _EVENT_LOG_MSG 1
+#define _EVENT_LOG_WARN 2
+#define _EVENT_LOG_ERR 3
+typedef void (*event_log_cb)(int severity, const char *msg);
+void event_set_log_callback(event_log_cb cb);
+
+void event_set (struct event *ev, int fd, short events, void (*cb)(int, short, void *), void *arg);
+int event_once (int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv);
+
+int event_add (struct event *ev, struct timeval *tv);
+int event_del (struct event *ev);
+void event_active (struct event *ev, int res, short ncalls); /* ncalls is being ignored */
+
+int event_pending (struct event *ev, short, struct timeval *tv);
+
+int event_priority_init (int npri);
+int event_priority_set (struct event *ev, int pri);
+
+struct event_base *event_base_new (void);
+const char *event_base_get_method (const struct event_base *);
+int event_base_set (struct event_base *base, struct event *ev);
+int event_base_loop (struct event_base *base, int);
+int event_base_loopexit (struct event_base *base, struct timeval *tv);
+int event_base_dispatch (struct event_base *base);
+int event_base_once (struct event_base *base, int fd, short events, void (*cb)(int, short, void *), void *arg, struct timeval *tv);
+int event_base_priority_init (struct event_base *base, int fd);
+
+/* next line is different in the libevent+libev version */
+/*libevent-include*/
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+
--- rxvt-unicode/libev/ev_epoll.c
+++ rxvt-unicode/libev/ev_epoll.c
@@ -235,10 +235,11 @@
}
}
-int inline_size
+inline_size
+int
epoll_init (EV_P_ int flags)
{
-#ifdef EPOLL_CLOEXEC
+#if defined EPOLL_CLOEXEC && !defined __ANDROID__
backend_fd = epoll_create1 (EPOLL_CLOEXEC);
if (backend_fd < 0 && (errno == EINVAL || errno == ENOSYS))
@@ -260,14 +261,16 @@
return EVBACKEND_EPOLL;
}
-void inline_size
+inline_size
+void
epoll_destroy (EV_P)
{
ev_free (epoll_events);
array_free (epoll_eperm, EMPTY);
}
-void inline_size
+inline_size
+void
epoll_fork (EV_P)
{
close (backend_fd);
--- rxvt-unicode/libev/ev.h
+++ rxvt-unicode/libev/ev.h
@@ -211,7 +211,7 @@
/*****************************************************************************/
#define EV_VERSION_MAJOR 4
-#define EV_VERSION_MINOR 22
+#define EV_VERSION_MINOR 24
/* eventmask, revents, events... */
enum {
@@ -515,10 +515,10 @@
/* method bits to be ored together */
enum {
- EVBACKEND_SELECT = 0x00000001U, /* about anywhere */
- EVBACKEND_POLL = 0x00000002U, /* !win */
+ EVBACKEND_SELECT = 0x00000001U, /* available just about anywhere */
+ EVBACKEND_POLL = 0x00000002U, /* !win, !aix, broken on osx */
EVBACKEND_EPOLL = 0x00000004U, /* linux */
- EVBACKEND_KQUEUE = 0x00000008U, /* bsd */
+ EVBACKEND_KQUEUE = 0x00000008U, /* bsd, broken on osx */
EVBACKEND_DEVPOLL = 0x00000010U, /* solaris 8 */ /* NYI */
EVBACKEND_PORT = 0x00000020U, /* solaris 10 */
EVBACKEND_ALL = 0x0000003FU, /* all known backends */
--- rxvt-unicode/libev/ev++.h
+++ rxvt-unicode/libev/ev++.h
@@ -175,7 +175,7 @@
bool operator != (const EV_P) const throw ()
{
- return (*this == EV_A);
+ return ! (*this == EV_A);
}
operator struct ev_loop * () const throw ()
--- rxvt-unicode/libev/ev_kqueue.c
+++ rxvt-unicode/libev/ev_kqueue.c
@@ -43,7 +43,8 @@
#include <string.h>
#include <errno.h>
-void inline_speed
+inline_speed
+void
kqueue_change (EV_P_ int fd, int filter, int flags, int fflags)
{
++kqueue_changecnt;
@@ -152,7 +153,8 @@
}
}
-int inline_size
+inline_size
+int
kqueue_init (EV_P_ int flags)
{
/* initialize the kernel queue */
@@ -176,14 +178,16 @@
return EVBACKEND_KQUEUE;
}
-void inline_size
+inline_size
+void
kqueue_destroy (EV_P)
{
ev_free (kqueue_events);
ev_free (kqueue_changes);
}
-void inline_size
+inline_size
+void
kqueue_fork (EV_P)
{
/* some BSD kernels don't just destroy the kqueue itself,
--- rxvt-unicode/libev/ev.pod
+++ rxvt-unicode/libev/ev.pod
@@ -0,0 +1,5570 @@
+=encoding utf-8
+
+=head1 NAME
+
+libev - a high performance full-featured event loop written in C
+
+=head1 SYNOPSIS
+
+ #include <ev.h>
+
+=head2 EXAMPLE PROGRAM
+
+ // a single header file is required
+ #include <ev.h>
+
+ #include <stdio.h> // for puts
+
+ // every watcher type has its own typedef'd struct
+ // with the name ev_TYPE
+ ev_io stdin_watcher;
+ ev_timer timeout_watcher;
+
+ // all watcher callbacks have a similar signature
+ // this callback is called when data is readable on stdin
+ static void
+ stdin_cb (EV_P_ ev_io *w, int revents)
+ {
+ puts ("stdin ready");
+ // for one-shot events, one must manually stop the watcher
+ // with its corresponding stop function.
+ ev_io_stop (EV_A_ w);
+
+ // this causes all nested ev_run's to stop iterating
+ ev_break (EV_A_ EVBREAK_ALL);
+ }
+
+ // another callback, this time for a time-out
+ static void
+ timeout_cb (EV_P_ ev_timer *w, int revents)
+ {
+ puts ("timeout");
+ // this causes the innermost ev_run to stop iterating
+ ev_break (EV_A_ EVBREAK_ONE);
+ }
+
+ int
+ main (void)
+ {
+ // use the default event loop unless you have special needs
+ struct ev_loop *loop = EV_DEFAULT;
+
+ // initialise an io watcher, then start it
+ // this one will watch for stdin to become readable
+ ev_io_init (&stdin_watcher, stdin_cb, /*STDIN_FILENO*/ 0, EV_READ);
+ ev_io_start (loop, &stdin_watcher);
+
+ // initialise a timer watcher, then start it
+ // simple non-repeating 5.5 second timeout
+ ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+ ev_timer_start (loop, &timeout_watcher);
+
+ // now wait for events to arrive
+ ev_run (loop, 0);
+
+ // break was called, so exit
+ return 0;
+ }
+
+=head1 ABOUT THIS DOCUMENT
+
+This document documents the libev software package.
+
+The newest version of this document is also available as an html-formatted
+web page you might find easier to navigate when reading it for the first
+time: L<http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod>.
+
+While this document tries to be as complete as possible in documenting
+libev, its usage and the rationale behind its design, it is not a tutorial
+on event-based programming, nor will it introduce event-based programming
+with libev.
+
+Familiarity with event based programming techniques in general is assumed
+throughout this document.
+
+=head1 WHAT TO READ WHEN IN A HURRY
+
+This manual tries to be very detailed, but unfortunately, this also makes
+it very long. If you just want to know the basics of libev, I suggest
+reading L</ANATOMY OF A WATCHER>, then the L</EXAMPLE PROGRAM> above and
+look up the missing functions in L</GLOBAL FUNCTIONS> and the C<ev_io> and
+C<ev_timer> sections in L</WATCHER TYPES>.
+
+=head1 ABOUT LIBEV
+
+Libev is an event loop: you register interest in certain events (such as a
+file descriptor being readable or a timeout occurring), and it will manage
+these event sources and provide your program with events.
+
+To do this, it must take more or less complete control over your process
+(or thread) by executing the I<event loop> handler, and will then
+communicate events via a callback mechanism.
+
+You register interest in certain events by registering so-called I<event
+watchers>, which are relatively small C structures you initialise with the
+details of the event, and then hand it over to libev by I<starting> the
+watcher.
+
+=head2 FEATURES
+
+Libev supports C<select>, C<poll>, the Linux-specific C<epoll>, the
+BSD-specific C<kqueue> and the Solaris-specific event port mechanisms
+for file descriptor events (C<ev_io>), the Linux C<inotify> interface
+(for C<ev_stat>), Linux eventfd/signalfd (for faster and cleaner
+inter-thread wakeup (C<ev_async>)/signal handling (C<ev_signal>)) relative
+timers (C<ev_timer>), absolute timers with customised rescheduling
+(C<ev_periodic>), synchronous signals (C<ev_signal>), process status
+change events (C<ev_child>), and event watchers dealing with the event
+loop mechanism itself (C<ev_idle>, C<ev_embed>, C<ev_prepare> and
+C<ev_check> watchers) as well as file watchers (C<ev_stat>) and even
+limited support for fork events (C<ev_fork>).
+
+It also is quite fast (see this
+L<benchmark|http://libev.schmorp.de/bench.html> comparing it to libevent
+for example).
+
+=head2 CONVENTIONS
+
+Libev is very configurable. In this manual the default (and most common)
+configuration will be described, which supports multiple event loops. For
+more info about various configuration options please have a look at
+B<EMBED> section in this manual. If libev was configured without support
+for multiple event loops, then all functions taking an initial argument of
+name C<loop> (which is always of type C<struct ev_loop *>) will not have
+this argument.
+
+=head2 TIME REPRESENTATION
+
+Libev represents time as a single floating point number, representing
+the (fractional) number of seconds since the (POSIX) epoch (in practice
+somewhere near the beginning of 1970, details are complicated, don't
+ask). This type is called C<ev_tstamp>, which is what you should use
+too. It usually aliases to the C<double> type in C. When you need to do
+any calculations on it, you should treat it as some floating point value.
+
+Unlike the name component C<stamp> might indicate, it is also used for
+time differences (e.g. delays) throughout libev.
+
+=head1 ERROR HANDLING
+
+Libev knows three classes of errors: operating system errors, usage errors
+and internal errors (bugs).
+
+When libev catches an operating system error it cannot handle (for example
+a system call indicating a condition libev cannot fix), it calls the callback
+set via C<ev_set_syserr_cb>, which is supposed to fix the problem or
+abort. The default is to print a diagnostic message and to call C<abort
+()>.
+
+When libev detects a usage error such as a negative timer interval, then
+it will print a diagnostic message and abort (via the C<assert> mechanism,
+so C<NDEBUG> will disable this checking): these are programming errors in
+the libev caller and need to be fixed there.
+
+Libev also has a few internal error-checking C<assert>ions, and also has
+extensive consistency checking code. These do not trigger under normal
+circumstances, as they indicate either a bug in libev or worse.
+
+
+=head1 GLOBAL FUNCTIONS
+
+These functions can be called anytime, even before initialising the
+library in any way.
+
+=over 4
+
+=item ev_tstamp ev_time ()
+
+Returns the current time as libev would use it. Please note that the
+C<ev_now> function is usually faster and also often returns the timestamp
+you actually want to know. Also interesting is the combination of
+C<ev_now_update> and C<ev_now>.
+
+=item ev_sleep (ev_tstamp interval)
+
+Sleep for the given interval: The current thread will be blocked
+until either it is interrupted or the given time interval has
+passed (approximately - it might return a bit earlier even if not
+interrupted). Returns immediately if C<< interval <= 0 >>.
+
+Basically this is a sub-second-resolution C<sleep ()>.
+
+The range of the C<interval> is limited - libev only guarantees to work
+with sleep times of up to one day (C<< interval <= 86400 >>).
+
+=item int ev_version_major ()
+
+=item int ev_version_minor ()
+
+You can find out the major and minor ABI version numbers of the library
+you linked against by calling the functions C<ev_version_major> and
+C<ev_version_minor>. If you want, you can compare against the global
+symbols C<EV_VERSION_MAJOR> and C<EV_VERSION_MINOR>, which specify the
+version of the library your program was compiled against.
+
+These version numbers refer to the ABI version of the library, not the
+release version.
+
+Usually, it's a good idea to terminate if the major versions mismatch,
+as this indicates an incompatible change. Minor versions are usually
+compatible to older versions, so a larger minor version alone is usually
+not a problem.
+
+Example: Make sure we haven't accidentally been linked against the wrong
+version (note, however, that this will not detect other ABI mismatches,
+such as LFS or reentrancy).
+
+ assert (("libev version mismatch",
+ ev_version_major () == EV_VERSION_MAJOR
+ && ev_version_minor () >= EV_VERSION_MINOR));
+
+=item unsigned int ev_supported_backends ()
+
+Return the set of all backends (i.e. their corresponding C<EV_BACKEND_*>
+value) compiled into this binary of libev (independent of their
+availability on the system you are running on). See C<ev_default_loop> for
+a description of the set values.
+
+Example: make sure we have the epoll method, because yeah this is cool and
+a must have and can we have a torrent of it please!!!11
+
+ assert (("sorry, no epoll, no sex",
+ ev_supported_backends () & EVBACKEND_EPOLL));
+
+=item unsigned int ev_recommended_backends ()
+
+Return the set of all backends compiled into this binary of libev and
+also recommended for this platform, meaning it will work for most file
+descriptor types. This set is often smaller than the one returned by
+C<ev_supported_backends>, as for example kqueue is broken on most BSDs
+and will not be auto-detected unless you explicitly request it (assuming
+you know what you are doing). This is the set of backends that libev will
+probe for if you specify no backends explicitly.
+
+=item unsigned int ev_embeddable_backends ()
+
+Returns the set of backends that are embeddable in other event loops. This
+value is platform-specific but can include backends not available on the
+current system. To find which embeddable backends might be supported on
+the current system, you would need to look at C<ev_embeddable_backends ()
+& ev_supported_backends ()>, likewise for recommended ones.
+
+See the description of C<ev_embed> watchers for more info.
+
+=item ev_set_allocator (void *(*cb)(void *ptr, long size) throw ())
+
+Sets the allocation function to use (the prototype is similar - the
+semantics are identical to the C<realloc> C89/SuS/POSIX function). It is
+used to allocate and free memory (no surprises here). If it returns zero
+when memory needs to be allocated (C<size != 0>), the library might abort
+or take some potentially destructive action.
+
+Since some systems (at least OpenBSD and Darwin) fail to implement
+correct C<realloc> semantics, libev will use a wrapper around the system
+C<realloc> and C<free> functions by default.
+
+You could override this function in high-availability programs to, say,
+free some memory if it cannot allocate memory, to use a special allocator,
+or even to sleep a while and retry until some memory is available.
+
+Example: Replace the libev allocator with one that waits a bit and then
+retries (example requires a standards-compliant C<realloc>).
+
+ static void *
+ persistent_realloc (void *ptr, size_t size)
+ {
+ for (;;)
+ {
+ void *newptr = realloc (ptr, size);
+
+ if (newptr)
+ return newptr;
+
+ sleep (60);
+ }
+ }
+
+ ...
+ ev_set_allocator (persistent_realloc);
+
+=item ev_set_syserr_cb (void (*cb)(const char *msg) throw ())
+
+Set the callback function to call on a retryable system call error (such
+as failed select, poll, epoll_wait). The message is a printable string
+indicating the system call or subsystem causing the problem. If this
+callback is set, then libev will expect it to remedy the situation, no
+matter what, when it returns. That is, libev will generally retry the
+requested operation, or, if the condition doesn't go away, do bad stuff
+(such as abort).
+
+Example: This is basically the same thing that libev does internally, too.
+
+ static void
+ fatal_error (const char *msg)
+ {
+ perror (msg);
+ abort ();
+ }
+
+ ...
+ ev_set_syserr_cb (fatal_error);
+
+=item ev_feed_signal (int signum)
+
+This function can be used to "simulate" a signal receive. It is completely
+safe to call this function at any time, from any context, including signal
+handlers or random threads.
+
+Its main use is to customise signal handling in your process, especially
+in the presence of threads. For example, you could block signals
+by default in all threads (and specifying C<EVFLAG_NOSIGMASK> when
+creating any loops), and in one thread, use C<sigwait> or any other
+mechanism to wait for signals, then "deliver" them to libev by calling
+C<ev_feed_signal>.
+
+=back
+
+=head1 FUNCTIONS CONTROLLING EVENT LOOPS
+
+An event loop is described by a C<struct ev_loop *> (the C<struct> is
+I<not> optional in this case unless libev 3 compatibility is disabled, as
+libev 3 had an C<ev_loop> function colliding with the struct name).
+
+The library knows two types of such loops, the I<default> loop, which
+supports child process events, and dynamically created event loops which
+do not.
+
+=over 4
+
+=item struct ev_loop *ev_default_loop (unsigned int flags)
+
+This returns the "default" event loop object, which is what you should
+normally use when you just need "the event loop". Event loop objects and
+the C<flags> parameter are described in more detail in the entry for
+C<ev_loop_new>.
+
+If the default loop is already initialised then this function simply
+returns it (and ignores the flags. If that is troubling you, check
+C<ev_backend ()> afterwards). Otherwise it will create it with the given
+flags, which should almost always be C<0>, unless the caller is also the
+one calling C<ev_run> or otherwise qualifies as "the main program".
+
+If you don't know what event loop to use, use the one returned from this
+function (or via the C<EV_DEFAULT> macro).
+
+Note that this function is I<not> thread-safe, so if you want to use it
+from multiple threads, you have to employ some kind of mutex (note also
+that this case is unlikely, as loops cannot be shared easily between
+threads anyway).
+
+The default loop is the only loop that can handle C<ev_child> watchers,
+and to do this, it always registers a handler for C<SIGCHLD>. If this is
+a problem for your application you can either create a dynamic loop with
+C<ev_loop_new> which doesn't do that, or you can simply overwrite the
+C<SIGCHLD> signal handler I<after> calling C<ev_default_init>.
+
+Example: This is the most typical usage.
+
+ if (!ev_default_loop (0))
+ fatal ("could not initialise libev, bad $LIBEV_FLAGS in environment?");
+
+Example: Restrict libev to the select and poll backends, and do not allow
+environment settings to be taken into account:
+
+ ev_default_loop (EVBACKEND_POLL | EVBACKEND_SELECT | EVFLAG_NOENV);
+
+=item struct ev_loop *ev_loop_new (unsigned int flags)
+
+This will create and initialise a new event loop object. If the loop
+could not be initialised, returns false.
+
+This function is thread-safe, and one common way to use libev with
+threads is indeed to create one loop per thread, and using the default
+loop in the "main" or "initial" thread.
+
+The flags argument can be used to specify special behaviour or specific
+backends to use, and is usually specified as C<0> (or C<EVFLAG_AUTO>).
+
+The following flags are supported:
+
+=over 4
+
+=item C<EVFLAG_AUTO>
+
+The default flags value. Use this if you have no clue (it's the right
+thing, believe me).
+
+=item C<EVFLAG_NOENV>
+
+If this flag bit is or'ed into the flag value (or the program runs setuid
+or setgid) then libev will I<not> look at the environment variable
+C<LIBEV_FLAGS>. Otherwise (the default), this environment variable will
+override the flags completely if it is found in the environment. This is
+useful to try out specific backends to test their performance, to work
+around bugs, or to make libev threadsafe (accessing environment variables
+cannot be done in a threadsafe way, but usually it works if no other
+thread modifies them).
+
+=item C<EVFLAG_FORKCHECK>
+
+Instead of calling C<ev_loop_fork> manually after a fork, you can also
+make libev check for a fork in each iteration by enabling this flag.
+
+This works by calling C<getpid ()> on every iteration of the loop,
+and thus this might slow down your event loop if you do a lot of loop
+iterations and little real work, but is usually not noticeable (on my
+GNU/Linux system for example, C<getpid> is actually a simple 5-insn
+sequence without a system call and thus I<very> fast, but my GNU/Linux
+system also has C<pthread_atfork> which is even faster). (Update: glibc
+versions 2.25 apparently removed the C<getpid> optimisation again).
+
+The big advantage of this flag is that you can forget about fork (and
+forget about forgetting to tell libev about forking, although you still
+have to ignore C<SIGPIPE>) when you use this flag.
+
+This flag setting cannot be overridden or specified in the C<LIBEV_FLAGS>
+environment variable.
+
+=item C<EVFLAG_NOINOTIFY>
+
+When this flag is specified, then libev will not attempt to use the
+I<inotify> API for its C<ev_stat> watchers. Apart from debugging and
+testing, this flag can be useful to conserve inotify file descriptors, as
+otherwise each loop using C<ev_stat> watchers consumes one inotify handle.
+
+=item C<EVFLAG_SIGNALFD>
+
+When this flag is specified, then libev will attempt to use the
+I<signalfd> API for its C<ev_signal> (and C<ev_child>) watchers. This API
+delivers signals synchronously, which makes it both faster and might make
+it possible to get the queued signal data. It can also simplify signal
+handling with threads, as long as you properly block signals in your
+threads that are not interested in handling them.
+
+Signalfd will not be used by default as this changes your signal mask, and
+there are a lot of shoddy libraries and programs (glib's threadpool for
+example) that can't properly initialise their signal masks.
+
+=item C<EVFLAG_NOSIGMASK>
+
+When this flag is specified, then libev will avoid to modify the signal
+mask. Specifically, this means you have to make sure signals are unblocked
+when you want to receive them.
+
+This behaviour is useful when you want to do your own signal handling, or
+want to handle signals only in specific threads and want to avoid libev
+unblocking the signals.
+
+It's also required by POSIX in a threaded program, as libev calls
+C<sigprocmask>, whose behaviour is officially unspecified.
+
+This flag's behaviour will become the default in future versions of libev.
+
+=item C<EVBACKEND_SELECT> (value 1, portable select backend)
+
+This is your standard select(2) backend. Not I<completely> standard, as
+libev tries to roll its own fd_set with no limits on the number of fds,
+but if that fails, expect a fairly low limit on the number of fds when
+using this backend. It doesn't scale too well (O(highest_fd)), but its
+usually the fastest backend for a low number of (low-numbered :) fds.
+
+To get good performance out of this backend you need a high amount of
+parallelism (most of the file descriptors should be busy). If you are
+writing a server, you should C<accept ()> in a loop to accept as many
+connections as possible during one iteration. You might also want to have
+a look at C<ev_set_io_collect_interval ()> to increase the amount of
+readiness notifications you get per iteration.
+
+This backend maps C<EV_READ> to the C<readfds> set and C<EV_WRITE> to the
+C<writefds> set (and to work around Microsoft Windows bugs, also onto the
+C<exceptfds> set on that platform).
+
+=item C<EVBACKEND_POLL> (value 2, poll backend, available everywhere except on windows)
+
+And this is your standard poll(2) backend. It's more complicated
+than select, but handles sparse fds better and has no artificial
+limit on the number of fds you can use (except it will slow down
+considerably with a lot of inactive fds). It scales similarly to select,
+i.e. O(total_fds). See the entry for C<EVBACKEND_SELECT>, above, for
+performance tips.
+
+This backend maps C<EV_READ> to C<POLLIN | POLLERR | POLLHUP>, and
+C<EV_WRITE> to C<POLLOUT | POLLERR | POLLHUP>.
+
+=item C<EVBACKEND_EPOLL> (value 4, Linux)
+
+Use the linux-specific epoll(7) interface (for both pre- and post-2.6.9
+kernels).
+
+For few fds, this backend is a bit little slower than poll and select, but
+it scales phenomenally better. While poll and select usually scale like
+O(total_fds) where total_fds is the total number of fds (or the highest
+fd), epoll scales either O(1) or O(active_fds).
+
+The epoll mechanism deserves honorable mention as the most misdesigned
+of the more advanced event mechanisms: mere annoyances include silently
+dropping file descriptors, requiring a system call per change per file
+descriptor (and unnecessary guessing of parameters), problems with dup,
+returning before the timeout value, resulting in additional iterations
+(and only giving 5ms accuracy while select on the same platform gives
+0.1ms) and so on. The biggest issue is fork races, however - if a program
+forks then I<both> parent and child process have to recreate the epoll
+set, which can take considerable time (one syscall per file descriptor)
+and is of course hard to detect.
+
+Epoll is also notoriously buggy - embedding epoll fds I<should> work,
+but of course I<doesn't>, and epoll just loves to report events for
+totally I<different> file descriptors (even already closed ones, so
+one cannot even remove them from the set) than registered in the set
+(especially on SMP systems). Libev tries to counter these spurious
+notifications by employing an additional generation counter and comparing
+that against the events to filter out spurious ones, recreating the set
+when required. Epoll also erroneously rounds down timeouts, but gives you
+no way to know when and by how much, so sometimes you have to busy-wait
+because epoll returns immediately despite a nonzero timeout. And last
+not least, it also refuses to work with some file descriptors which work
+perfectly fine with C<select> (files, many character devices...).
+
+Epoll is truly the train wreck among event poll mechanisms, a frankenpoll,
+cobbled together in a hurry, no thought to design or interaction with
+others. Oh, the pain, will it ever stop...
+
+While stopping, setting and starting an I/O watcher in the same iteration
+will result in some caching, there is still a system call per such
+incident (because the same I<file descriptor> could point to a different
+I<file description> now), so its best to avoid that. Also, C<dup ()>'ed
+file descriptors might not work very well if you register events for both
+file descriptors.
+
+Best performance from this backend is achieved by not unregistering all
+watchers for a file descriptor until it has been closed, if possible,
+i.e. keep at least one watcher active per fd at all times. Stopping and
+starting a watcher (without re-setting it) also usually doesn't cause
+extra overhead. A fork can both result in spurious notifications as well
+as in libev having to destroy and recreate the epoll object, which can
+take considerable time and thus should be avoided.
+
+All this means that, in practice, C<EVBACKEND_SELECT> can be as fast or
+faster than epoll for maybe up to a hundred file descriptors, depending on
+the usage. So sad.
+
+While nominally embeddable in other event loops, this feature is broken in
+all kernel versions tested so far.
+
+This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
+C<EVBACKEND_POLL>.
+
+=item C<EVBACKEND_KQUEUE> (value 8, most BSD clones)
+
+Kqueue deserves special mention, as at the time of this writing, it
+was broken on all BSDs except NetBSD (usually it doesn't work reliably
+with anything but sockets and pipes, except on Darwin, where of course
+it's completely useless). Unlike epoll, however, whose brokenness
+is by design, these kqueue bugs can (and eventually will) be fixed
+without API changes to existing programs. For this reason it's not being
+"auto-detected" unless you explicitly specify it in the flags (i.e. using
+C<EVBACKEND_KQUEUE>) or libev was compiled on a known-to-be-good (-enough)
+system like NetBSD.
+
+You still can embed kqueue into a normal poll or select backend and use it
+only for sockets (after having made sure that sockets work with kqueue on
+the target platform). See C<ev_embed> watchers for more info.
+
+It scales in the same way as the epoll backend, but the interface to the
+kernel is more efficient (which says nothing about its actual speed, of
+course). While stopping, setting and starting an I/O watcher does never
+cause an extra system call as with C<EVBACKEND_EPOLL>, it still adds up to
+two event changes per incident. Support for C<fork ()> is very bad (you
+might have to leak fd's on fork, but it's more sane than epoll) and it
+drops fds silently in similarly hard-to-detect cases.
+
+This backend usually performs well under most conditions.
+
+While nominally embeddable in other event loops, this doesn't work
+everywhere, so you might need to test for this. And since it is broken
+almost everywhere, you should only use it when you have a lot of sockets
+(for which it usually works), by embedding it into another event loop
+(e.g. C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> (but C<poll> is of course
+also broken on OS X)) and, did I mention it, using it only for sockets.
+
+This backend maps C<EV_READ> into an C<EVFILT_READ> kevent with
+C<NOTE_EOF>, and C<EV_WRITE> into an C<EVFILT_WRITE> kevent with
+C<NOTE_EOF>.
+
+=item C<EVBACKEND_DEVPOLL> (value 16, Solaris 8)
+
+This is not implemented yet (and might never be, unless you send me an
+implementation). According to reports, C</dev/poll> only supports sockets
+and is not embeddable, which would limit the usefulness of this backend
+immensely.
+
+=item C<EVBACKEND_PORT> (value 32, Solaris 10)
+
+This uses the Solaris 10 event port mechanism. As with everything on Solaris,
+it's really slow, but it still scales very well (O(active_fds)).
+
+While this backend scales well, it requires one system call per active
+file descriptor per loop iteration. For small and medium numbers of file
+descriptors a "slow" C<EVBACKEND_SELECT> or C<EVBACKEND_POLL> backend
+might perform better.
+
+On the positive side, this backend actually performed fully to
+specification in all tests and is fully embeddable, which is a rare feat
+among the OS-specific backends (I vastly prefer correctness over speed
+hacks).
+
+On the negative side, the interface is I<bizarre> - so bizarre that
+even sun itself gets it wrong in their code examples: The event polling
+function sometimes returns events to the caller even though an error
+occurred, but with no indication whether it has done so or not (yes, it's
+even documented that way) - deadly for edge-triggered interfaces where you
+absolutely have to know whether an event occurred or not because you have
+to re-arm the watcher.
+
+Fortunately libev seems to be able to work around these idiocies.
+
+This backend maps C<EV_READ> and C<EV_WRITE> in the same way as
+C<EVBACKEND_POLL>.
+
+=item C<EVBACKEND_ALL>
+
+Try all backends (even potentially broken ones that wouldn't be tried
+with C<EVFLAG_AUTO>). Since this is a mask, you can do stuff such as
+C<EVBACKEND_ALL & ~EVBACKEND_KQUEUE>.
+
+It is definitely not recommended to use this flag, use whatever
+C<ev_recommended_backends ()> returns, or simply do not specify a backend
+at all.
+
+=item C<EVBACKEND_MASK>
+
+Not a backend at all, but a mask to select all backend bits from a
+C<flags> value, in case you want to mask out any backends from a flags
+value (e.g. when modifying the C<LIBEV_FLAGS> environment variable).
+
+=back
+
+If one or more of the backend flags are or'ed into the flags value,
+then only these backends will be tried (in the reverse order as listed
+here). If none are specified, all backends in C<ev_recommended_backends
+()> will be tried.
+
+Example: Try to create a event loop that uses epoll and nothing else.
+
+ struct ev_loop *epoller = ev_loop_new (EVBACKEND_EPOLL | EVFLAG_NOENV);
+ if (!epoller)
+ fatal ("no epoll found here, maybe it hides under your chair");
+
+Example: Use whatever libev has to offer, but make sure that kqueue is
+used if available.
+
+ struct ev_loop *loop = ev_loop_new (ev_recommended_backends () | EVBACKEND_KQUEUE);
+
+=item ev_loop_destroy (loop)
+
+Destroys an event loop object (frees all memory and kernel state
+etc.). None of the active event watchers will be stopped in the normal
+sense, so e.g. C<ev_is_active> might still return true. It is your
+responsibility to either stop all watchers cleanly yourself I<before>
+calling this function, or cope with the fact afterwards (which is usually
+the easiest thing, you can just ignore the watchers and/or C<free ()> them
+for example).
+
+Note that certain global state, such as signal state (and installed signal
+handlers), will not be freed by this function, and related watchers (such
+as signal and child watchers) would need to be stopped manually.
+
+This function is normally used on loop objects allocated by
+C<ev_loop_new>, but it can also be used on the default loop returned by
+C<ev_default_loop>, in which case it is not thread-safe.
+
+Note that it is not advisable to call this function on the default loop
+except in the rare occasion where you really need to free its resources.
+If you need dynamically allocated loops it is better to use C<ev_loop_new>
+and C<ev_loop_destroy>.
+
+=item ev_loop_fork (loop)
+
+This function sets a flag that causes subsequent C<ev_run> iterations
+to reinitialise the kernel state for backends that have one. Despite
+the name, you can call it anytime you are allowed to start or stop
+watchers (except inside an C<ev_prepare> callback), but it makes most
+sense after forking, in the child process. You I<must> call it (or use
+C<EVFLAG_FORKCHECK>) in the child before resuming or calling C<ev_run>.
+
+In addition, if you want to reuse a loop (via this function or
+C<EVFLAG_FORKCHECK>), you I<also> have to ignore C<SIGPIPE>.
+
+Again, you I<have> to call it on I<any> loop that you want to re-use after
+a fork, I<even if you do not plan to use the loop in the parent>. This is
+because some kernel interfaces *cough* I<kqueue> *cough* do funny things
+during fork.
+
+On the other hand, you only need to call this function in the child
+process if and only if you want to use the event loop in the child. If
+you just fork+exec or create a new loop in the child, you don't have to
+call it at all (in fact, C<epoll> is so badly broken that it makes a
+difference, but libev will usually detect this case on its own and do a
+costly reset of the backend).
+
+The function itself is quite fast and it's usually not a problem to call
+it just in case after a fork.
+
+Example: Automate calling C<ev_loop_fork> on the default loop when
+using pthreads.
+
+ static void
+ post_fork_child (void)
+ {
+ ev_loop_fork (EV_DEFAULT);
+ }
+
+ ...
+ pthread_atfork (0, 0, post_fork_child);
+
+=item int ev_is_default_loop (loop)
+
+Returns true when the given loop is, in fact, the default loop, and false
+otherwise.
+
+=item unsigned int ev_iteration (loop)
+
+Returns the current iteration count for the event loop, which is identical
+to the number of times libev did poll for new events. It starts at C<0>
+and happily wraps around with enough iterations.
+
+This value can sometimes be useful as a generation counter of sorts (it
+"ticks" the number of loop iterations), as it roughly corresponds with
+C<ev_prepare> and C<ev_check> calls - and is incremented between the
+prepare and check phases.
+
+=item unsigned int ev_depth (loop)
+
+Returns the number of times C<ev_run> was entered minus the number of
+times C<ev_run> was exited normally, in other words, the recursion depth.
+
+Outside C<ev_run>, this number is zero. In a callback, this number is
+C<1>, unless C<ev_run> was invoked recursively (or from another thread),
+in which case it is higher.
+
+Leaving C<ev_run> abnormally (setjmp/longjmp, cancelling the thread,
+throwing an exception etc.), doesn't count as "exit" - consider this
+as a hint to avoid such ungentleman-like behaviour unless it's really
+convenient, in which case it is fully supported.
+
+=item unsigned int ev_backend (loop)
+
+Returns one of the C<EVBACKEND_*> flags indicating the event backend in
+use.
+
+=item ev_tstamp ev_now (loop)
+
+Returns the current "event loop time", which is the time the event loop
+received events and started processing them. This timestamp does not
+change as long as callbacks are being processed, and this is also the base
+time used for relative timers. You can treat it as the timestamp of the
+event occurring (or more correctly, libev finding out about it).
+
+=item ev_now_update (loop)
+
+Establishes the current time by querying the kernel, updating the time
+returned by C<ev_now ()> in the progress. This is a costly operation and
+is usually done automatically within C<ev_run ()>.
+
+This function is rarely useful, but when some event callback runs for a
+very long time without entering the event loop, updating libev's idea of
+the current time is a good idea.
+
+See also L</The special problem of time updates> in the C<ev_timer> section.
+
+=item ev_suspend (loop)
+
+=item ev_resume (loop)
+
+These two functions suspend and resume an event loop, for use when the
+loop is not used for a while and timeouts should not be processed.
+
+A typical use case would be an interactive program such as a game: When
+the user presses C<^Z> to suspend the game and resumes it an hour later it
+would be best to handle timeouts as if no time had actually passed while
+the program was suspended. This can be achieved by calling C<ev_suspend>
+in your C<SIGTSTP> handler, sending yourself a C<SIGSTOP> and calling
+C<ev_resume> directly afterwards to resume timer processing.
+
+Effectively, all C<ev_timer> watchers will be delayed by the time spend
+between C<ev_suspend> and C<ev_resume>, and all C<ev_periodic> watchers
+will be rescheduled (that is, they will lose any events that would have
+occurred while suspended).
+
+After calling C<ev_suspend> you B<must not> call I<any> function on the
+given loop other than C<ev_resume>, and you B<must not> call C<ev_resume>
+without a previous call to C<ev_suspend>.
+
+Calling C<ev_suspend>/C<ev_resume> has the side effect of updating the
+event loop time (see C<ev_now_update>).
+
+=item bool ev_run (loop, int flags)
+
+Finally, this is it, the event handler. This function usually is called
+after you have initialised all your watchers and you want to start
+handling events. It will ask the operating system for any new events, call
+the watcher callbacks, and then repeat the whole process indefinitely: This
+is why event loops are called I<loops>.
+
+If the flags argument is specified as C<0>, it will keep handling events
+until either no event watchers are active anymore or C<ev_break> was
+called.
+
+The return value is false if there are no more active watchers (which
+usually means "all jobs done" or "deadlock"), and true in all other cases
+(which usually means " you should call C<ev_run> again").
+
+Please note that an explicit C<ev_break> is usually better than
+relying on all watchers to be stopped when deciding when a program has
+finished (especially in interactive programs), but having a program
+that automatically loops as long as it has to and no longer by virtue
+of relying on its watchers stopping correctly, that is truly a thing of
+beauty.
+
+This function is I<mostly> exception-safe - you can break out of a
+C<ev_run> call by calling C<longjmp> in a callback, throwing a C++
+exception and so on. This does not decrement the C<ev_depth> value, nor
+will it clear any outstanding C<EVBREAK_ONE> breaks.
+
+A flags value of C<EVRUN_NOWAIT> will look for new events, will handle
+those events and any already outstanding ones, but will not wait and
+block your process in case there are no events and will return after one
+iteration of the loop. This is sometimes useful to poll and handle new
+events while doing lengthy calculations, to keep the program responsive.
+
+A flags value of C<EVRUN_ONCE> will look for new events (waiting if
+necessary) and will handle those and any already outstanding ones. It
+will block your process until at least one new event arrives (which could
+be an event internal to libev itself, so there is no guarantee that a
+user-registered callback will be called), and will return after one
+iteration of the loop.
+
+This is useful if you are waiting for some external event in conjunction
+with something not expressible using other libev watchers (i.e. "roll your
+own C<ev_run>"). However, a pair of C<ev_prepare>/C<ev_check> watchers is
+usually a better approach for this kind of thing.
+
+Here are the gory details of what C<ev_run> does (this is for your
+understanding, not a guarantee that things will work exactly like this in
+future versions):
+
+ - Increment loop depth.
+ - Reset the ev_break status.
+ - Before the first iteration, call any pending watchers.
+ LOOP:
+ - If EVFLAG_FORKCHECK was used, check for a fork.
+ - If a fork was detected (by any means), queue and call all fork watchers.
+ - Queue and call all prepare watchers.
+ - If ev_break was called, goto FINISH.
+ - If we have been forked, detach and recreate the kernel state
+ as to not disturb the other process.
+ - Update the kernel state with all outstanding changes.
+ - Update the "event loop time" (ev_now ()).
+ - Calculate for how long to sleep or block, if at all
+ (active idle watchers, EVRUN_NOWAIT or not having
+ any active watchers at all will result in not sleeping).
+ - Sleep if the I/O and timer collect interval say so.
+ - Increment loop iteration counter.
+ - Block the process, waiting for any events.
+ - Queue all outstanding I/O (fd) events.
+ - Update the "event loop time" (ev_now ()), and do time jump adjustments.
+ - Queue all expired timers.
+ - Queue all expired periodics.
+ - Queue all idle watchers with priority higher than that of pending events.
+ - Queue all check watchers.
+ - Call all queued watchers in reverse order (i.e. check watchers first).
+ Signals and child watchers are implemented as I/O watchers, and will
+ be handled here by queueing them when their watcher gets executed.
+ - If ev_break has been called, or EVRUN_ONCE or EVRUN_NOWAIT
+ were used, or there are no active watchers, goto FINISH, otherwise
+ continue with step LOOP.
+ FINISH:
+ - Reset the ev_break status iff it was EVBREAK_ONE.
+ - Decrement the loop depth.
+ - Return.
+
+Example: Queue some jobs and then loop until no events are outstanding
+anymore.
+
+ ... queue jobs here, make sure they register event watchers as long
+ ... as they still have work to do (even an idle watcher will do..)
+ ev_run (my_loop, 0);
+ ... jobs done or somebody called break. yeah!
+
+=item ev_break (loop, how)
+
+Can be used to make a call to C<ev_run> return early (but only after it
+has processed all outstanding events). The C<how> argument must be either
+C<EVBREAK_ONE>, which will make the innermost C<ev_run> call return, or
+C<EVBREAK_ALL>, which will make all nested C<ev_run> calls return.
+
+This "break state" will be cleared on the next call to C<ev_run>.
+
+It is safe to call C<ev_break> from outside any C<ev_run> calls, too, in
+which case it will have no effect.
+
+=item ev_ref (loop)
+
+=item ev_unref (loop)
+
+Ref/unref can be used to add or remove a reference count on the event
+loop: Every watcher keeps one reference, and as long as the reference
+count is nonzero, C<ev_run> will not return on its own.
+
+This is useful when you have a watcher that you never intend to
+unregister, but that nevertheless should not keep C<ev_run> from
+returning. In such a case, call C<ev_unref> after starting, and C<ev_ref>
+before stopping it.
+
+As an example, libev itself uses this for its internal signal pipe: It
+is not visible to the libev user and should not keep C<ev_run> from
+exiting if no event watchers registered by it are active. It is also an
+excellent way to do this for generic recurring timers or from within
+third-party libraries. Just remember to I<unref after start> and I<ref
+before stop> (but only if the watcher wasn't active before, or was active
+before, respectively. Note also that libev might stop watchers itself
+(e.g. non-repeating timers) in which case you have to C<ev_ref>
+in the callback).
+
+Example: Create a signal watcher, but keep it from keeping C<ev_run>
+running when nothing else is active.
+
+ ev_signal exitsig;
+ ev_signal_init (&exitsig, sig_cb, SIGINT);
+ ev_signal_start (loop, &exitsig);
+ ev_unref (loop);
+
+Example: For some weird reason, unregister the above signal handler again.
+
+ ev_ref (loop);
+ ev_signal_stop (loop, &exitsig);
+
+=item ev_set_io_collect_interval (loop, ev_tstamp interval)
+
+=item ev_set_timeout_collect_interval (loop, ev_tstamp interval)
+
+These advanced functions influence the time that libev will spend waiting
+for events. Both time intervals are by default C<0>, meaning that libev
+will try to invoke timer/periodic callbacks and I/O callbacks with minimum
+latency.
+
+Setting these to a higher value (the C<interval> I<must> be >= C<0>)
+allows libev to delay invocation of I/O and timer/periodic callbacks
+to increase efficiency of loop iterations (or to increase power-saving
+opportunities).
+
+The idea is that sometimes your program runs just fast enough to handle
+one (or very few) event(s) per loop iteration. While this makes the
+program responsive, it also wastes a lot of CPU time to poll for new
+events, especially with backends like C<select ()> which have a high
+overhead for the actual polling but can deliver many events at once.
+
+By setting a higher I<io collect interval> you allow libev to spend more
+time collecting I/O events, so you can handle more events per iteration,
+at the cost of increasing latency. Timeouts (both C<ev_periodic> and
+C<ev_timer>) will not be affected. Setting this to a non-null value will
+introduce an additional C<ev_sleep ()> call into most loop iterations. The
+sleep time ensures that libev will not poll for I/O events more often then
+once per this interval, on average (as long as the host time resolution is
+good enough).
+
+Likewise, by setting a higher I<timeout collect interval> you allow libev
+to spend more time collecting timeouts, at the expense of increased
+latency/jitter/inexactness (the watcher callback will be called
+later). C<ev_io> watchers will not be affected. Setting this to a non-null
+value will not introduce any overhead in libev.
+
+Many (busy) programs can usually benefit by setting the I/O collect
+interval to a value near C<0.1> or so, which is often enough for
+interactive servers (of course not for games), likewise for timeouts. It
+usually doesn't make much sense to set it to a lower value than C<0.01>,
+as this approaches the timing granularity of most systems. Note that if
+you do transactions with the outside world and you can't increase the
+parallelity, then this setting will limit your transaction rate (if you
+need to poll once per transaction and the I/O collect interval is 0.01,
+then you can't do more than 100 transactions per second).
+
+Setting the I<timeout collect interval> can improve the opportunity for
+saving power, as the program will "bundle" timer callback invocations that
+are "near" in time together, by delaying some, thus reducing the number of
+times the process sleeps and wakes up again. Another useful technique to
+reduce iterations/wake-ups is to use C<ev_periodic> watchers and make sure
+they fire on, say, one-second boundaries only.
+
+Example: we only need 0.1s timeout granularity, and we wish not to poll
+more often than 100 times per second:
+
+ ev_set_timeout_collect_interval (EV_DEFAULT_UC_ 0.1);
+ ev_set_io_collect_interval (EV_DEFAULT_UC_ 0.01);
+
+=item ev_invoke_pending (loop)
+
+This call will simply invoke all pending watchers while resetting their
+pending state. Normally, C<ev_run> does this automatically when required,
+but when overriding the invoke callback this call comes handy. This
+function can be invoked from a watcher - this can be useful for example
+when you want to do some lengthy calculation and want to pass further
+event handling to another thread (you still have to make sure only one
+thread executes within C<ev_invoke_pending> or C<ev_run> of course).
+
+=item int ev_pending_count (loop)
+
+Returns the number of pending watchers - zero indicates that no watchers
+are pending.
+
+=item ev_set_invoke_pending_cb (loop, void (*invoke_pending_cb)(EV_P))
+
+This overrides the invoke pending functionality of the loop: Instead of
+invoking all pending watchers when there are any, C<ev_run> will call
+this callback instead. This is useful, for example, when you want to
+invoke the actual watchers inside another context (another thread etc.).
+
+If you want to reset the callback, use C<ev_invoke_pending> as new
+callback.
+
+=item ev_set_loop_release_cb (loop, void (*release)(EV_P) throw (), void (*acquire)(EV_P) throw ())
+
+Sometimes you want to share the same loop between multiple threads. This
+can be done relatively simply by putting mutex_lock/unlock calls around
+each call to a libev function.
+
+However, C<ev_run> can run an indefinite time, so it is not feasible
+to wait for it to return. One way around this is to wake up the event
+loop via C<ev_break> and C<ev_async_send>, another way is to set these
+I<release> and I<acquire> callbacks on the loop.
+
+When set, then C<release> will be called just before the thread is
+suspended waiting for new events, and C<acquire> is called just
+afterwards.
+
+Ideally, C<release> will just call your mutex_unlock function, and
+C<acquire> will just call the mutex_lock function again.
+
+While event loop modifications are allowed between invocations of
+C<release> and C<acquire> (that's their only purpose after all), no
+modifications done will affect the event loop, i.e. adding watchers will
+have no effect on the set of file descriptors being watched, or the time
+waited. Use an C<ev_async> watcher to wake up C<ev_run> when you want it
+to take note of any changes you made.
+
+In theory, threads executing C<ev_run> will be async-cancel safe between
+invocations of C<release> and C<acquire>.
+
+See also the locking example in the C<THREADS> section later in this
+document.
+
+=item ev_set_userdata (loop, void *data)
+
+=item void *ev_userdata (loop)
+
+Set and retrieve a single C<void *> associated with a loop. When
+C<ev_set_userdata> has never been called, then C<ev_userdata> returns
+C<0>.
+
+These two functions can be used to associate arbitrary data with a loop,
+and are intended solely for the C<invoke_pending_cb>, C<release> and
+C<acquire> callbacks described above, but of course can be (ab-)used for
+any other purpose as well.
+
+=item ev_verify (loop)
+
+This function only does something when C<EV_VERIFY> support has been
+compiled in, which is the default for non-minimal builds. It tries to go
+through all internal structures and checks them for validity. If anything
+is found to be inconsistent, it will print an error message to standard
+error and call C<abort ()>.
+
+This can be used to catch bugs inside libev itself: under normal
+circumstances, this function will never abort as of course libev keeps its
+data structures consistent.
+
+=back
+
+
+=head1 ANATOMY OF A WATCHER
+
+In the following description, uppercase C<TYPE> in names stands for the
+watcher type, e.g. C<ev_TYPE_start> can mean C<ev_timer_start> for timer
+watchers and C<ev_io_start> for I/O watchers.
+
+A watcher is an opaque structure that you allocate and register to record
+your interest in some event. To make a concrete example, imagine you want
+to wait for STDIN to become readable, you would create an C<ev_io> watcher
+for that:
+
+ static void my_cb (struct ev_loop *loop, ev_io *w, int revents)
+ {
+ ev_io_stop (w);
+ ev_break (loop, EVBREAK_ALL);
+ }
+
+ struct ev_loop *loop = ev_default_loop (0);
+
+ ev_io stdin_watcher;
+
+ ev_init (&stdin_watcher, my_cb);
+ ev_io_set (&stdin_watcher, STDIN_FILENO, EV_READ);
+ ev_io_start (loop, &stdin_watcher);
+
+ ev_run (loop, 0);
+
+As you can see, you are responsible for allocating the memory for your
+watcher structures (and it is I<usually> a bad idea to do this on the
+stack).
+
+Each watcher has an associated watcher structure (called C<struct ev_TYPE>
+or simply C<ev_TYPE>, as typedefs are provided for all watcher structs).
+
+Each watcher structure must be initialised by a call to C<ev_init (watcher
+*, callback)>, which expects a callback to be provided. This callback is
+invoked each time the event occurs (or, in the case of I/O watchers, each
+time the event loop detects that the file descriptor given is readable
+and/or writable).
+
+Each watcher type further has its own C<< ev_TYPE_set (watcher *, ...) >>
+macro to configure it, with arguments specific to the watcher type. There
+is also a macro to combine initialisation and setting in one call: C<<
+ev_TYPE_init (watcher *, callback, ...) >>.
+
+To make the watcher actually watch out for events, you have to start it
+with a watcher-specific start function (C<< ev_TYPE_start (loop, watcher
+*) >>), and you can stop watching for events at any time by calling the
+corresponding stop function (C<< ev_TYPE_stop (loop, watcher *) >>.
+
+As long as your watcher is active (has been started but not stopped) you
+must not touch the values stored in it. Most specifically you must never
+reinitialise it or call its C<ev_TYPE_set> macro.
+
+Each and every callback receives the event loop pointer as first, the
+registered watcher structure as second, and a bitset of received events as
+third argument.
+
+The received events usually include a single bit per event type received
+(you can receive multiple events at the same time). The possible bit masks
+are:
+
+=over 4
+
+=item C<EV_READ>
+
+=item C<EV_WRITE>
+
+The file descriptor in the C<ev_io> watcher has become readable and/or
+writable.
+
+=item C<EV_TIMER>
+
+The C<ev_timer> watcher has timed out.
+
+=item C<EV_PERIODIC>
+
+The C<ev_periodic> watcher has timed out.
+
+=item C<EV_SIGNAL>
+
+The signal specified in the C<ev_signal> watcher has been received by a thread.
+
+=item C<EV_CHILD>
+
+The pid specified in the C<ev_child> watcher has received a status change.
+
+=item C<EV_STAT>
+
+The path specified in the C<ev_stat> watcher changed its attributes somehow.
+
+=item C<EV_IDLE>
+
+The C<ev_idle> watcher has determined that you have nothing better to do.
+
+=item C<EV_PREPARE>
+
+=item C<EV_CHECK>
+
+All C<ev_prepare> watchers are invoked just I<before> C<ev_run> starts to
+gather new events, and all C<ev_check> watchers are queued (not invoked)
+just after C<ev_run> has gathered them, but before it queues any callbacks
+for any received events. That means C<ev_prepare> watchers are the last
+watchers invoked before the event loop sleeps or polls for new events, and
+C<ev_check> watchers will be invoked before any other watchers of the same
+or lower priority within an event loop iteration.
+
+Callbacks of both watcher types can start and stop as many watchers as
+they want, and all of them will be taken into account (for example, a
+C<ev_prepare> watcher might start an idle watcher to keep C<ev_run> from
+blocking).
+
+=item C<EV_EMBED>
+
+The embedded event loop specified in the C<ev_embed> watcher needs attention.
+
+=item C<EV_FORK>
+
+The event loop has been resumed in the child process after fork (see
+C<ev_fork>).
+
+=item C<EV_CLEANUP>
+
+The event loop is about to be destroyed (see C<ev_cleanup>).
+
+=item C<EV_ASYNC>
+
+The given async watcher has been asynchronously notified (see C<ev_async>).
+
+=item C<EV_CUSTOM>
+
+Not ever sent (or otherwise used) by libev itself, but can be freely used
+by libev users to signal watchers (e.g. via C<ev_feed_event>).
+
+=item C<EV_ERROR>
+
+An unspecified error has occurred, the watcher has been stopped. This might
+happen because the watcher could not be properly started because libev
+ran out of memory, a file descriptor was found to be closed or any other
+problem. Libev considers these application bugs.
+
+You best act on it by reporting the problem and somehow coping with the
+watcher being stopped. Note that well-written programs should not receive
+an error ever, so when your watcher receives it, this usually indicates a
+bug in your program.
+
+Libev will usually signal a few "dummy" events together with an error, for
+example it might indicate that a fd is readable or writable, and if your
+callbacks is well-written it can just attempt the operation and cope with
+the error from read() or write(). This will not work in multi-threaded
+programs, though, as the fd could already be closed and reused for another
+thing, so beware.
+
+=back
+
+=head2 GENERIC WATCHER FUNCTIONS
+
+=over 4
+
+=item C<ev_init> (ev_TYPE *watcher, callback)
+
+This macro initialises the generic portion of a watcher. The contents
+of the watcher object can be arbitrary (so C<malloc> will do). Only
+the generic parts of the watcher are initialised, you I<need> to call
+the type-specific C<ev_TYPE_set> macro afterwards to initialise the
+type-specific parts. For each type there is also a C<ev_TYPE_init> macro
+which rolls both calls into one.
+
+You can reinitialise a watcher at any time as long as it has been stopped
+(or never started) and there are no pending events outstanding.
+
+The callback is always of type C<void (*)(struct ev_loop *loop, ev_TYPE *watcher,
+int revents)>.
+
+Example: Initialise an C<ev_io> watcher in two steps.
+
+ ev_io w;
+ ev_init (&w, my_cb);
+ ev_io_set (&w, STDIN_FILENO, EV_READ);
+
+=item C<ev_TYPE_set> (ev_TYPE *watcher, [args])
+
+This macro initialises the type-specific parts of a watcher. You need to
+call C<ev_init> at least once before you call this macro, but you can
+call C<ev_TYPE_set> any number of times. You must not, however, call this
+macro on a watcher that is active (it can be pending, however, which is a
+difference to the C<ev_init> macro).
+
+Although some watcher types do not have type-specific arguments
+(e.g. C<ev_prepare>) you still need to call its C<set> macro.
+
+See C<ev_init>, above, for an example.
+
+=item C<ev_TYPE_init> (ev_TYPE *watcher, callback, [args])
+
+This convenience macro rolls both C<ev_init> and C<ev_TYPE_set> macro
+calls into a single call. This is the most convenient method to initialise
+a watcher. The same limitations apply, of course.
+
+Example: Initialise and set an C<ev_io> watcher in one step.
+
+ ev_io_init (&w, my_cb, STDIN_FILENO, EV_READ);
+
+=item C<ev_TYPE_start> (loop, ev_TYPE *watcher)
+
+Starts (activates) the given watcher. Only active watchers will receive
+events. If the watcher is already active nothing will happen.
+
+Example: Start the C<ev_io> watcher that is being abused as example in this
+whole section.
+
+ ev_io_start (EV_DEFAULT_UC, &w);
+
+=item C<ev_TYPE_stop> (loop, ev_TYPE *watcher)
+
+Stops the given watcher if active, and clears the pending status (whether
+the watcher was active or not).
+
+It is possible that stopped watchers are pending - for example,
+non-repeating timers are being stopped when they become pending - but
+calling C<ev_TYPE_stop> ensures that the watcher is neither active nor
+pending. If you want to free or reuse the memory used by the watcher it is
+therefore a good idea to always call its C<ev_TYPE_stop> function.
+
+=item bool ev_is_active (ev_TYPE *watcher)
+
+Returns a true value iff the watcher is active (i.e. it has been started
+and not yet been stopped). As long as a watcher is active you must not modify
+it.
+
+=item bool ev_is_pending (ev_TYPE *watcher)
+
+Returns a true value iff the watcher is pending, (i.e. it has outstanding
+events but its callback has not yet been invoked). As long as a watcher
+is pending (but not active) you must not call an init function on it (but
+C<ev_TYPE_set> is safe), you must not change its priority, and you must
+make sure the watcher is available to libev (e.g. you cannot C<free ()>
+it).
+
+=item callback ev_cb (ev_TYPE *watcher)
+
+Returns the callback currently set on the watcher.
+
+=item ev_set_cb (ev_TYPE *watcher, callback)
+
+Change the callback. You can change the callback at virtually any time
+(modulo threads).
+
+=item ev_set_priority (ev_TYPE *watcher, int priority)
+
+=item int ev_priority (ev_TYPE *watcher)
+
+Set and query the priority of the watcher. The priority is a small
+integer between C<EV_MAXPRI> (default: C<2>) and C<EV_MINPRI>
+(default: C<-2>). Pending watchers with higher priority will be invoked
+before watchers with lower priority, but priority will not keep watchers
+from being executed (except for C<ev_idle> watchers).
+
+If you need to suppress invocation when higher priority events are pending
+you need to look at C<ev_idle> watchers, which provide this functionality.
+
+You I<must not> change the priority of a watcher as long as it is active or
+pending.
+
+Setting a priority outside the range of C<EV_MINPRI> to C<EV_MAXPRI> is
+fine, as long as you do not mind that the priority value you query might
+or might not have been clamped to the valid range.
+
+The default priority used by watchers when no priority has been set is
+always C<0>, which is supposed to not be too high and not be too low :).
+
+See L</WATCHER PRIORITY MODELS>, below, for a more thorough treatment of
+priorities.
+
+=item ev_invoke (loop, ev_TYPE *watcher, int revents)
+
+Invoke the C<watcher> with the given C<loop> and C<revents>. Neither
+C<loop> nor C<revents> need to be valid as long as the watcher callback
+can deal with that fact, as both are simply passed through to the
+callback.
+
+=item int ev_clear_pending (loop, ev_TYPE *watcher)
+
+If the watcher is pending, this function clears its pending status and
+returns its C<revents> bitset (as if its callback was invoked). If the
+watcher isn't pending it does nothing and returns C<0>.
+
+Sometimes it can be useful to "poll" a watcher instead of waiting for its
+callback to be invoked, which can be accomplished with this function.
+
+=item ev_feed_event (loop, ev_TYPE *watcher, int revents)
+
+Feeds the given event set into the event loop, as if the specified event
+had happened for the specified watcher (which must be a pointer to an
+initialised but not necessarily started event watcher). Obviously you must
+not free the watcher as long as it has pending events.
+
+Stopping the watcher, letting libev invoke it, or calling
+C<ev_clear_pending> will clear the pending event, even if the watcher was
+not started in the first place.
+
+See also C<ev_feed_fd_event> and C<ev_feed_signal_event> for related
+functions that do not need a watcher.
+
+=back
+
+See also the L</ASSOCIATING CUSTOM DATA WITH A WATCHER> and L</BUILDING YOUR
+OWN COMPOSITE WATCHERS> idioms.
+
+=head2 WATCHER STATES
+
+There are various watcher states mentioned throughout this manual -
+active, pending and so on. In this section these states and the rules to
+transition between them will be described in more detail - and while these
+rules might look complicated, they usually do "the right thing".
+
+=over 4
+
+=item initialised
+
+Before a watcher can be registered with the event loop it has to be
+initialised. This can be done with a call to C<ev_TYPE_init>, or calls to
+C<ev_init> followed by the watcher-specific C<ev_TYPE_set> function.
+
+In this state it is simply some block of memory that is suitable for
+use in an event loop. It can be moved around, freed, reused etc. at
+will - as long as you either keep the memory contents intact, or call
+C<ev_TYPE_init> again.
+
+=item started/running/active
+
+Once a watcher has been started with a call to C<ev_TYPE_start> it becomes
+property of the event loop, and is actively waiting for events. While in
+this state it cannot be accessed (except in a few documented ways), moved,
+freed or anything else - the only legal thing is to keep a pointer to it,
+and call libev functions on it that are documented to work on active watchers.
+
+=item pending
+
+If a watcher is active and libev determines that an event it is interested
+in has occurred (such as a timer expiring), it will become pending. It will
+stay in this pending state until either it is stopped or its callback is
+about to be invoked, so it is not normally pending inside the watcher
+callback.
+
+The watcher might or might not be active while it is pending (for example,
+an expired non-repeating timer can be pending but no longer active). If it
+is stopped, it can be freely accessed (e.g. by calling C<ev_TYPE_set>),
+but it is still property of the event loop at this time, so cannot be
+moved, freed or reused. And if it is active the rules described in the
+previous item still apply.
+
+It is also possible to feed an event on a watcher that is not active (e.g.
+via C<ev_feed_event>), in which case it becomes pending without being
+active.
+
+=item stopped
+
+A watcher can be stopped implicitly by libev (in which case it might still
+be pending), or explicitly by calling its C<ev_TYPE_stop> function. The
+latter will clear any pending state the watcher might be in, regardless
+of whether it was active or not, so stopping a watcher explicitly before
+freeing it is often a good idea.
+
+While stopped (and not pending) the watcher is essentially in the
+initialised state, that is, it can be reused, moved, modified in any way
+you wish (but when you trash the memory block, you need to C<ev_TYPE_init>
+it again).
+
+=back
+
+=head2 WATCHER PRIORITY MODELS
+
+Many event loops support I<watcher priorities>, which are usually small
+integers that influence the ordering of event callback invocation
+between watchers in some way, all else being equal.
+
+In libev, Watcher priorities can be set using C<ev_set_priority>. See its
+description for the more technical details such as the actual priority
+range.
+
+There are two common ways how these these priorities are being interpreted
+by event loops:
+
+In the more common lock-out model, higher priorities "lock out" invocation
+of lower priority watchers, which means as long as higher priority
+watchers receive events, lower priority watchers are not being invoked.
+
+The less common only-for-ordering model uses priorities solely to order
+callback invocation within a single event loop iteration: Higher priority
+watchers are invoked before lower priority ones, but they all get invoked
+before polling for new events.
+
+Libev uses the second (only-for-ordering) model for all its watchers
+except for idle watchers (which use the lock-out model).
+
+The rationale behind this is that implementing the lock-out model for
+watchers is not well supported by most kernel interfaces, and most event
+libraries will just poll for the same events again and again as long as
+their callbacks have not been executed, which is very inefficient in the
+common case of one high-priority watcher locking out a mass of lower
+priority ones.
+
+Static (ordering) priorities are most useful when you have two or more
+watchers handling the same resource: a typical usage example is having an
+C<ev_io> watcher to receive data, and an associated C<ev_timer> to handle
+timeouts. Under load, data might be received while the program handles
+other jobs, but since timers normally get invoked first, the timeout
+handler will be executed before checking for data. In that case, giving
+the timer a lower priority than the I/O watcher ensures that I/O will be
+handled first even under adverse conditions (which is usually, but not
+always, what you want).
+
+Since idle watchers use the "lock-out" model, meaning that idle watchers
+will only be executed when no same or higher priority watchers have
+received events, they can be used to implement the "lock-out" model when
+required.
+
+For example, to emulate how many other event libraries handle priorities,
+you can associate an C<ev_idle> watcher to each such watcher, and in
+the normal watcher callback, you just start the idle watcher. The real
+processing is done in the idle watcher callback. This causes libev to
+continuously poll and process kernel event data for the watcher, but when
+the lock-out case is known to be rare (which in turn is rare :), this is
+workable.
+
+Usually, however, the lock-out model implemented that way will perform
+miserably under the type of load it was designed to handle. In that case,
+it might be preferable to stop the real watcher before starting the
+idle watcher, so the kernel will not have to process the event in case
+the actual processing will be delayed for considerable time.
+
+Here is an example of an I/O watcher that should run at a strictly lower
+priority than the default, and which should only process data when no
+other events are pending:
+
+ ev_idle idle; // actual processing watcher
+ ev_io io; // actual event watcher
+
+ static void
+ io_cb (EV_P_ ev_io *w, int revents)
+ {
+ // stop the I/O watcher, we received the event, but
+ // are not yet ready to handle it.
+ ev_io_stop (EV_A_ w);
+
+ // start the idle watcher to handle the actual event.
+ // it will not be executed as long as other watchers
+ // with the default priority are receiving events.
+ ev_idle_start (EV_A_ &idle);
+ }
+
+ static void
+ idle_cb (EV_P_ ev_idle *w, int revents)
+ {
+ // actual processing
+ read (STDIN_FILENO, ...);
+
+ // have to start the I/O watcher again, as
+ // we have handled the event
+ ev_io_start (EV_P_ &io);
+ }
+
+ // initialisation
+ ev_idle_init (&idle, idle_cb);
+ ev_io_init (&io, io_cb, STDIN_FILENO, EV_READ);
+ ev_io_start (EV_DEFAULT_ &io);
+
+In the "real" world, it might also be beneficial to start a timer, so that
+low-priority connections can not be locked out forever under load. This
+enables your program to keep a lower latency for important connections
+during short periods of high load, while not completely locking out less
+important ones.
+
+
+=head1 WATCHER TYPES
+
+This section describes each watcher in detail, but will not repeat
+information given in the last section. Any initialisation/set macros,
+functions and members specific to the watcher type are explained.
+
+Members are additionally marked with either I<[read-only]>, meaning that,
+while the watcher is active, you can look at the member and expect some
+sensible content, but you must not modify it (you can modify it while the
+watcher is stopped to your hearts content), or I<[read-write]>, which
+means you can expect it to have some sensible content while the watcher
+is active, but you can also modify it. Modifying it may not do something
+sensible or take immediate effect (or do anything at all), but libev will
+not crash or malfunction in any way.
+
+
+=head2 C<ev_io> - is this file descriptor readable or writable?
+
+I/O watchers check whether a file descriptor is readable or writable
+in each iteration of the event loop, or, more precisely, when reading
+would not block the process and writing would at least be able to write
+some data. This behaviour is called level-triggering because you keep
+receiving events as long as the condition persists. Remember you can stop
+the watcher if you don't want to act on the event and neither want to
+receive future events.
+
+In general you can register as many read and/or write event watchers per
+fd as you want (as long as you don't confuse yourself). Setting all file
+descriptors to non-blocking mode is also usually a good idea (but not
+required if you know what you are doing).
+
+Another thing you have to watch out for is that it is quite easy to
+receive "spurious" readiness notifications, that is, your callback might
+be called with C<EV_READ> but a subsequent C<read>(2) will actually block
+because there is no data. It is very easy to get into this situation even
+with a relatively standard program structure. Thus it is best to always
+use non-blocking I/O: An extra C<read>(2) returning C<EAGAIN> is far
+preferable to a program hanging until some data arrives.
+
+If you cannot run the fd in non-blocking mode (for example you should
+not play around with an Xlib connection), then you have to separately
+re-test whether a file descriptor is really ready with a known-to-be good
+interface such as poll (fortunately in the case of Xlib, it already does
+this on its own, so its quite safe to use). Some people additionally
+use C<SIGALRM> and an interval timer, just to be sure you won't block
+indefinitely.
+
+But really, best use non-blocking mode.
+
+=head3 The special problem of disappearing file descriptors
+
+Some backends (e.g. kqueue, epoll) need to be told about closing a file
+descriptor (either due to calling C<close> explicitly or any other means,
+such as C<dup2>). The reason is that you register interest in some file
+descriptor, but when it goes away, the operating system will silently drop
+this interest. If another file descriptor with the same number then is
+registered with libev, there is no efficient way to see that this is, in
+fact, a different file descriptor.
+
+To avoid having to explicitly tell libev about such cases, libev follows
+the following policy: Each time C<ev_io_set> is being called, libev
+will assume that this is potentially a new file descriptor, otherwise
+it is assumed that the file descriptor stays the same. That means that
+you I<have> to call C<ev_io_set> (or C<ev_io_init>) when you change the
+descriptor even if the file descriptor number itself did not change.
+
+This is how one would do it normally anyway, the important point is that
+the libev application should not optimise around libev but should leave
+optimisations to libev.
+
+=head3 The special problem of dup'ed file descriptors
+
+Some backends (e.g. epoll), cannot register events for file descriptors,
+but only events for the underlying file descriptions. That means when you
+have C<dup ()>'ed file descriptors or weirder constellations, and register
+events for them, only one file descriptor might actually receive events.
+
+There is no workaround possible except not registering events
+for potentially C<dup ()>'ed file descriptors, or to resort to
+C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.
+
+=head3 The special problem of files
+
+Many people try to use C<select> (or libev) on file descriptors
+representing files, and expect it to become ready when their program
+doesn't block on disk accesses (which can take a long time on their own).
+
+However, this cannot ever work in the "expected" way - you get a readiness
+notification as soon as the kernel knows whether and how much data is
+there, and in the case of open files, that's always the case, so you
+always get a readiness notification instantly, and your read (or possibly
+write) will still block on the disk I/O.
+
+Another way to view it is that in the case of sockets, pipes, character
+devices and so on, there is another party (the sender) that delivers data
+on its own, but in the case of files, there is no such thing: the disk
+will not send data on its own, simply because it doesn't know what you
+wish to read - you would first have to request some data.
+
+Since files are typically not-so-well supported by advanced notification
+mechanism, libev tries hard to emulate POSIX behaviour with respect
+to files, even though you should not use it. The reason for this is
+convenience: sometimes you want to watch STDIN or STDOUT, which is
+usually a tty, often a pipe, but also sometimes files or special devices
+(for example, C<epoll> on Linux works with F</dev/random> but not with
+F</dev/urandom>), and even though the file might better be served with
+asynchronous I/O instead of with non-blocking I/O, it is still useful when
+it "just works" instead of freezing.
+
+So avoid file descriptors pointing to files when you know it (e.g. use
+libeio), but use them when it is convenient, e.g. for STDIN/STDOUT, or
+when you rarely read from a file instead of from a socket, and want to
+reuse the same code path.
+
+=head3 The special problem of fork
+
+Some backends (epoll, kqueue) do not support C<fork ()> at all or exhibit
+useless behaviour. Libev fully supports fork, but needs to be told about
+it in the child if you want to continue to use it in the child.
+
+To support fork in your child processes, you have to call C<ev_loop_fork
+()> after a fork in the child, enable C<EVFLAG_FORKCHECK>, or resort to
+C<EVBACKEND_SELECT> or C<EVBACKEND_POLL>.
+
+=head3 The special problem of SIGPIPE
+
+While not really specific to libev, it is easy to forget about C<SIGPIPE>:
+when writing to a pipe whose other end has been closed, your program gets
+sent a SIGPIPE, which, by default, aborts your program. For most programs
+this is sensible behaviour, for daemons, this is usually undesirable.
+
+So when you encounter spurious, unexplained daemon exits, make sure you
+ignore SIGPIPE (and maybe make sure you log the exit status of your daemon
+somewhere, as that would have given you a big clue).
+
+=head3 The special problem of accept()ing when you can't
+
+Many implementations of the POSIX C<accept> function (for example,
+found in post-2004 Linux) have the peculiar behaviour of not removing a
+connection from the pending queue in all error cases.
+
+For example, larger servers often run out of file descriptors (because
+of resource limits), causing C<accept> to fail with C<ENFILE> but not
+rejecting the connection, leading to libev signalling readiness on
+the next iteration again (the connection still exists after all), and
+typically causing the program to loop at 100% CPU usage.
+
+Unfortunately, the set of errors that cause this issue differs between
+operating systems, there is usually little the app can do to remedy the
+situation, and no known thread-safe method of removing the connection to
+cope with overload is known (to me).
+
+One of the easiest ways to handle this situation is to just ignore it
+- when the program encounters an overload, it will just loop until the
+situation is over. While this is a form of busy waiting, no OS offers an
+event-based way to handle this situation, so it's the best one can do.
+
+A better way to handle the situation is to log any errors other than
+C<EAGAIN> and C<EWOULDBLOCK>, making sure not to flood the log with such
+messages, and continue as usual, which at least gives the user an idea of
+what could be wrong ("raise the ulimit!"). For extra points one could stop
+the C<ev_io> watcher on the listening fd "for a while", which reduces CPU
+usage.
+
+If your program is single-threaded, then you could also keep a dummy file
+descriptor for overload situations (e.g. by opening F</dev/null>), and
+when you run into C<ENFILE> or C<EMFILE>, close it, run C<accept>,
+close that fd, and create a new dummy fd. This will gracefully refuse
+clients under typical overload conditions.
+
+The last way to handle it is to simply log the error and C<exit>, as
+is often done with C<malloc> failures, but this results in an easy
+opportunity for a DoS attack.
+
+=head3 Watcher-Specific Functions
+
+=over 4
+
+=item ev_io_init (ev_io *, callback, int fd, int events)
+
+=item ev_io_set (ev_io *, int fd, int events)
+
+Configures an C<ev_io> watcher. The C<fd> is the file descriptor to
+receive events for and C<events> is either C<EV_READ>, C<EV_WRITE> or
+C<EV_READ | EV_WRITE>, to express the desire to receive the given events.
+
+=item int fd [read-only]
+
+The file descriptor being watched.
+
+=item int events [read-only]
+
+The events being watched.
+
+=back
+
+=head3 Examples
+
+Example: Call C<stdin_readable_cb> when STDIN_FILENO has become, well
+readable, but only once. Since it is likely line-buffered, you could
+attempt to read a whole line in the callback.
+
+ static void
+ stdin_readable_cb (struct ev_loop *loop, ev_io *w, int revents)
+ {
+ ev_io_stop (loop, w);
+ .. read from stdin here (or from w->fd) and handle any I/O errors
+ }
+
+ ...
+ struct ev_loop *loop = ev_default_init (0);
+ ev_io stdin_readable;
+ ev_io_init (&stdin_readable, stdin_readable_cb, STDIN_FILENO, EV_READ);
+ ev_io_start (loop, &stdin_readable);
+ ev_run (loop, 0);
+
+
+=head2 C<ev_timer> - relative and optionally repeating timeouts
+
+Timer watchers are simple relative timers that generate an event after a
+given time, and optionally repeating in regular intervals after that.
+
+The timers are based on real time, that is, if you register an event that
+times out after an hour and you reset your system clock to January last
+year, it will still time out after (roughly) one hour. "Roughly" because
+detecting time jumps is hard, and some inaccuracies are unavoidable (the
+monotonic clock option helps a lot here).
+
+The callback is guaranteed to be invoked only I<after> its timeout has
+passed (not I<at>, so on systems with very low-resolution clocks this
+might introduce a small delay, see "the special problem of being too
+early", below). If multiple timers become ready during the same loop
+iteration then the ones with earlier time-out values are invoked before
+ones of the same priority with later time-out values (but this is no
+longer true when a callback calls C<ev_run> recursively).
+
+=head3 Be smart about timeouts
+
+Many real-world problems involve some kind of timeout, usually for error
+recovery. A typical example is an HTTP request - if the other side hangs,
+you want to raise some error after a while.
+
+What follows are some ways to handle this problem, from obvious and
+inefficient to smart and efficient.
+
+In the following, a 60 second activity timeout is assumed - a timeout that
+gets reset to 60 seconds each time there is activity (e.g. each time some
+data or other life sign was received).
+
+=over 4
+
+=item 1. Use a timer and stop, reinitialise and start it on activity.
+
+This is the most obvious, but not the most simple way: In the beginning,
+start the watcher:
+
+ ev_timer_init (timer, callback, 60., 0.);
+ ev_timer_start (loop, timer);
+
+Then, each time there is some activity, C<ev_timer_stop> it, initialise it
+and start it again:
+
+ ev_timer_stop (loop, timer);
+ ev_timer_set (timer, 60., 0.);
+ ev_timer_start (loop, timer);
+
+This is relatively simple to implement, but means that each time there is
+some activity, libev will first have to remove the timer from its internal
+data structure and then add it again. Libev tries to be fast, but it's
+still not a constant-time operation.
+
+=item 2. Use a timer and re-start it with C<ev_timer_again> inactivity.
+
+This is the easiest way, and involves using C<ev_timer_again> instead of
+C<ev_timer_start>.
+
+To implement this, configure an C<ev_timer> with a C<repeat> value
+of C<60> and then call C<ev_timer_again> at start and each time you
+successfully read or write some data. If you go into an idle state where
+you do not expect data to travel on the socket, you can C<ev_timer_stop>
+the timer, and C<ev_timer_again> will automatically restart it if need be.
+
+That means you can ignore both the C<ev_timer_start> function and the
+C<after> argument to C<ev_timer_set>, and only ever use the C<repeat>
+member and C<ev_timer_again>.
+
+At start:
+
+ ev_init (timer, callback);
+ timer->repeat = 60.;
+ ev_timer_again (loop, timer);
+
+Each time there is some activity:
+
+ ev_timer_again (loop, timer);
+
+It is even possible to change the time-out on the fly, regardless of
+whether the watcher is active or not:
+
+ timer->repeat = 30.;
+ ev_timer_again (loop, timer);
+
+This is slightly more efficient then stopping/starting the timer each time
+you want to modify its timeout value, as libev does not have to completely
+remove and re-insert the timer from/into its internal data structure.
+
+It is, however, even simpler than the "obvious" way to do it.
+
+=item 3. Let the timer time out, but then re-arm it as required.
+
+This method is more tricky, but usually most efficient: Most timeouts are
+relatively long compared to the intervals between other activity - in
+our example, within 60 seconds, there are usually many I/O events with
+associated activity resets.
+
+In this case, it would be more efficient to leave the C<ev_timer> alone,
+but remember the time of last activity, and check for a real timeout only
+within the callback:
+
+ ev_tstamp timeout = 60.;
+ ev_tstamp last_activity; // time of last activity
+ ev_timer timer;
+
+ static void
+ callback (EV_P_ ev_timer *w, int revents)
+ {
+ // calculate when the timeout would happen
+ ev_tstamp after = last_activity - ev_now (EV_A) + timeout;
+
+ // if negative, it means we the timeout already occurred
+ if (after < 0.)
+ {
+ // timeout occurred, take action
+ }
+ else
+ {
+ // callback was invoked, but there was some recent
+ // activity. simply restart the timer to time out
+ // after "after" seconds, which is the earliest time
+ // the timeout can occur.
+ ev_timer_set (w, after, 0.);
+ ev_timer_start (EV_A_ w);
+ }
+ }
+
+To summarise the callback: first calculate in how many seconds the
+timeout will occur (by calculating the absolute time when it would occur,
+C<last_activity + timeout>, and subtracting the current time, C<ev_now
+(EV_A)> from that).
+
+If this value is negative, then we are already past the timeout, i.e. we
+timed out, and need to do whatever is needed in this case.
+
+Otherwise, we now the earliest time at which the timeout would trigger,
+and simply start the timer with this timeout value.
+
+In other words, each time the callback is invoked it will check whether
+the timeout occurred. If not, it will simply reschedule itself to check
+again at the earliest time it could time out. Rinse. Repeat.
+
+This scheme causes more callback invocations (about one every 60 seconds
+minus half the average time between activity), but virtually no calls to
+libev to change the timeout.
+
+To start the machinery, simply initialise the watcher and set
+C<last_activity> to the current time (meaning there was some activity just
+now), then call the callback, which will "do the right thing" and start
+the timer:
+
+ last_activity = ev_now (EV_A);
+ ev_init (&timer, callback);
+ callback (EV_A_ &timer, 0);
+
+When there is some activity, simply store the current time in
+C<last_activity>, no libev calls at all:
+
+ if (activity detected)
+ last_activity = ev_now (EV_A);
+
+When your timeout value changes, then the timeout can be changed by simply
+providing a new value, stopping the timer and calling the callback, which
+will again do the right thing (for example, time out immediately :).
+
+ timeout = new_value;
+ ev_timer_stop (EV_A_ &timer);
+ callback (EV_A_ &timer, 0);
+
+This technique is slightly more complex, but in most cases where the
+time-out is unlikely to be triggered, much more efficient.
+
+=item 4. Wee, just use a double-linked list for your timeouts.
+
+If there is not one request, but many thousands (millions...), all
+employing some kind of timeout with the same timeout value, then one can
+do even better:
+
+When starting the timeout, calculate the timeout value and put the timeout
+at the I<end> of the list.
+
+Then use an C<ev_timer> to fire when the timeout at the I<beginning> of
+the list is expected to fire (for example, using the technique #3).
+
+When there is some activity, remove the timer from the list, recalculate
+the timeout, append it to the end of the list again, and make sure to
+update the C<ev_timer> if it was taken from the beginning of the list.
+
+This way, one can manage an unlimited number of timeouts in O(1) time for
+starting, stopping and updating the timers, at the expense of a major
+complication, and having to use a constant timeout. The constant timeout
+ensures that the list stays sorted.
+
+=back
+
+So which method the best?
+
+Method #2 is a simple no-brain-required solution that is adequate in most
+situations. Method #3 requires a bit more thinking, but handles many cases
+better, and isn't very complicated either. In most case, choosing either
+one is fine, with #3 being better in typical situations.
+
+Method #1 is almost always a bad idea, and buys you nothing. Method #4 is
+rather complicated, but extremely efficient, something that really pays
+off after the first million or so of active timers, i.e. it's usually
+overkill :)
+
+=head3 The special problem of being too early
+
+If you ask a timer to call your callback after three seconds, then
+you expect it to be invoked after three seconds - but of course, this
+cannot be guaranteed to infinite precision. Less obviously, it cannot be
+guaranteed to any precision by libev - imagine somebody suspending the
+process with a STOP signal for a few hours for example.
+
+So, libev tries to invoke your callback as soon as possible I<after> the
+delay has occurred, but cannot guarantee this.
+
+A less obvious failure mode is calling your callback too early: many event
+loops compare timestamps with a "elapsed delay >= requested delay", but
+this can cause your callback to be invoked much earlier than you would
+expect.
+
+To see why, imagine a system with a clock that only offers full second
+resolution (think windows if you can't come up with a broken enough OS
+yourself). If you schedule a one-second timer at the time 500.9, then the
+event loop will schedule your timeout to elapse at a system time of 500
+(500.9 truncated to the resolution) + 1, or 501.
+
+If an event library looks at the timeout 0.1s later, it will see "501 >=
+501" and invoke the callback 0.1s after it was started, even though a
+one-second delay was requested - this is being "too early", despite best
+intentions.
+
+This is the reason why libev will never invoke the callback if the elapsed
+delay equals the requested delay, but only when the elapsed delay is
+larger than the requested delay. In the example above, libev would only invoke
+the callback at system time 502, or 1.1s after the timer was started.
+
+So, while libev cannot guarantee that your callback will be invoked
+exactly when requested, it I<can> and I<does> guarantee that the requested
+delay has actually elapsed, or in other words, it always errs on the "too
+late" side of things.
+
+=head3 The special problem of time updates
+
+Establishing the current time is a costly operation (it usually takes
+at least one system call): EV therefore updates its idea of the current
+time only before and after C<ev_run> collects new events, which causes a
+growing difference between C<ev_now ()> and C<ev_time ()> when handling
+lots of events in one iteration.
+
+The relative timeouts are calculated relative to the C<ev_now ()>
+time. This is usually the right thing as this timestamp refers to the time
+of the event triggering whatever timeout you are modifying/starting. If
+you suspect event processing to be delayed and you I<need> to base the
+timeout on the current time, use something like the following to adjust
+for it:
+
+ ev_timer_set (&timer, after + (ev_time () - ev_now ()), 0.);
+
+If the event loop is suspended for a long time, you can also force an
+update of the time returned by C<ev_now ()> by calling C<ev_now_update
+()>, although that will push the event time of all outstanding events
+further into the future.
+
+=head3 The special problem of unsynchronised clocks
+
+Modern systems have a variety of clocks - libev itself uses the normal
+"wall clock" clock and, if available, the monotonic clock (to avoid time
+jumps).
+
+Neither of these clocks is synchronised with each other or any other clock
+on the system, so C<ev_time ()> might return a considerably different time
+than C<gettimeofday ()> or C<time ()>. On a GNU/Linux system, for example,
+a call to C<gettimeofday> might return a second count that is one higher
+than a directly following call to C<time>.
+
+The moral of this is to only compare libev-related timestamps with
+C<ev_time ()> and C<ev_now ()>, at least if you want better precision than
+a second or so.
+
+One more problem arises due to this lack of synchronisation: if libev uses
+the system monotonic clock and you compare timestamps from C<ev_time>
+or C<ev_now> from when you started your timer and when your callback is
+invoked, you will find that sometimes the callback is a bit "early".
+
+This is because C<ev_timer>s work in real time, not wall clock time, so
+libev makes sure your callback is not invoked before the delay happened,
+I<measured according to the real time>, not the system clock.
+
+If your timeouts are based on a physical timescale (e.g. "time out this
+connection after 100 seconds") then this shouldn't bother you as it is
+exactly the right behaviour.
+
+If you want to compare wall clock/system timestamps to your timers, then
+you need to use C<ev_periodic>s, as these are based on the wall clock
+time, where your comparisons will always generate correct results.
+
+=head3 The special problems of suspended animation
+
+When you leave the server world it is quite customary to hit machines that
+can suspend/hibernate - what happens to the clocks during such a suspend?
+
+Some quick tests made with a Linux 2.6.28 indicate that a suspend freezes
+all processes, while the clocks (C<times>, C<CLOCK_MONOTONIC>) continue
+to run until the system is suspended, but they will not advance while the
+system is suspended. That means, on resume, it will be as if the program
+was frozen for a few seconds, but the suspend time will not be counted
+towards C<ev_timer> when a monotonic clock source is used. The real time
+clock advanced as expected, but if it is used as sole clocksource, then a
+long suspend would be detected as a time jump by libev, and timers would
+be adjusted accordingly.
+
+I would not be surprised to see different behaviour in different between
+operating systems, OS versions or even different hardware.
+
+The other form of suspend (job control, or sending a SIGSTOP) will see a
+time jump in the monotonic clocks and the realtime clock. If the program
+is suspended for a very long time, and monotonic clock sources are in use,
+then you can expect C<ev_timer>s to expire as the full suspension time
+will be counted towards the timers. When no monotonic clock source is in
+use, then libev will again assume a timejump and adjust accordingly.
+
+It might be beneficial for this latter case to call C<ev_suspend>
+and C<ev_resume> in code that handles C<SIGTSTP>, to at least get
+deterministic behaviour in this case (you can do nothing against
+C<SIGSTOP>).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_timer_init (ev_timer *, callback, ev_tstamp after, ev_tstamp repeat)
+
+=item ev_timer_set (ev_timer *, ev_tstamp after, ev_tstamp repeat)
+
+Configure the timer to trigger after C<after> seconds. If C<repeat>
+is C<0.>, then it will automatically be stopped once the timeout is
+reached. If it is positive, then the timer will automatically be
+configured to trigger again C<repeat> seconds later, again, and again,
+until stopped manually.
+
+The timer itself will do a best-effort at avoiding drift, that is, if
+you configure a timer to trigger every 10 seconds, then it will normally
+trigger at exactly 10 second intervals. If, however, your program cannot
+keep up with the timer (because it takes longer than those 10 seconds to
+do stuff) the timer will not fire more than once per event loop iteration.
+
+=item ev_timer_again (loop, ev_timer *)
+
+This will act as if the timer timed out, and restarts it again if it is
+repeating. It basically works like calling C<ev_timer_stop>, updating the
+timeout to the C<repeat> value and calling C<ev_timer_start>.
+
+The exact semantics are as in the following rules, all of which will be
+applied to the watcher:
+
+=over 4
+
+=item If the timer is pending, the pending status is always cleared.
+
+=item If the timer is started but non-repeating, stop it (as if it timed
+out, without invoking it).
+
+=item If the timer is repeating, make the C<repeat> value the new timeout
+and start the timer, if necessary.
+
+=back
+
+This sounds a bit complicated, see L</Be smart about timeouts>, above, for a
+usage example.
+
+=item ev_tstamp ev_timer_remaining (loop, ev_timer *)
+
+Returns the remaining time until a timer fires. If the timer is active,
+then this time is relative to the current event loop time, otherwise it's
+the timeout value currently configured.
+
+That is, after an C<ev_timer_set (w, 5, 7)>, C<ev_timer_remaining> returns
+C<5>. When the timer is started and one second passes, C<ev_timer_remaining>
+will return C<4>. When the timer expires and is restarted, it will return
+roughly C<7> (likely slightly less as callback invocation takes some time,
+too), and so on.
+
+=item ev_tstamp repeat [read-write]
+
+The current C<repeat> value. Will be used each time the watcher times out
+or C<ev_timer_again> is called, and determines the next timeout (if any),
+which is also when any modifications are taken into account.
+
+=back
+
+=head3 Examples
+
+Example: Create a timer that fires after 60 seconds.
+
+ static void
+ one_minute_cb (struct ev_loop *loop, ev_timer *w, int revents)
+ {
+ .. one minute over, w is actually stopped right here
+ }
+
+ ev_timer mytimer;
+ ev_timer_init (&mytimer, one_minute_cb, 60., 0.);
+ ev_timer_start (loop, &mytimer);
+
+Example: Create a timeout timer that times out after 10 seconds of
+inactivity.
+
+ static void
+ timeout_cb (struct ev_loop *loop, ev_timer *w, int revents)
+ {
+ .. ten seconds without any activity
+ }
+
+ ev_timer mytimer;
+ ev_timer_init (&mytimer, timeout_cb, 0., 10.); /* note, only repeat used */
+ ev_timer_again (&mytimer); /* start timer */
+ ev_run (loop, 0);
+
+ // and in some piece of code that gets executed on any "activity":
+ // reset the timeout to start ticking again at 10 seconds
+ ev_timer_again (&mytimer);
+
+
+=head2 C<ev_periodic> - to cron or not to cron?
+
+Periodic watchers are also timers of a kind, but they are very versatile
+(and unfortunately a bit complex).
+
+Unlike C<ev_timer>, periodic watchers are not based on real time (or
+relative time, the physical time that passes) but on wall clock time
+(absolute time, the thing you can read on your calendar or clock). The
+difference is that wall clock time can run faster or slower than real
+time, and time jumps are not uncommon (e.g. when you adjust your
+wrist-watch).
+
+You can tell a periodic watcher to trigger after some specific point
+in time: for example, if you tell a periodic watcher to trigger "in 10
+seconds" (by specifying e.g. C<ev_now () + 10.>, that is, an absolute time
+not a delay) and then reset your system clock to January of the previous
+year, then it will take a year or more to trigger the event (unlike an
+C<ev_timer>, which would still trigger roughly 10 seconds after starting
+it, as it uses a relative timeout).
+
+C<ev_periodic> watchers can also be used to implement vastly more complex
+timers, such as triggering an event on each "midnight, local time", or
+other complicated rules. This cannot be done with C<ev_timer> watchers, as
+those cannot react to time jumps.
+
+As with timers, the callback is guaranteed to be invoked only when the
+point in time where it is supposed to trigger has passed. If multiple
+timers become ready during the same loop iteration then the ones with
+earlier time-out values are invoked before ones with later time-out values
+(but this is no longer true when a callback calls C<ev_run> recursively).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_periodic_init (ev_periodic *, callback, ev_tstamp offset, ev_tstamp interval, reschedule_cb)
+
+=item ev_periodic_set (ev_periodic *, ev_tstamp offset, ev_tstamp interval, reschedule_cb)
+
+Lots of arguments, let's sort it out... There are basically three modes of
+operation, and we will explain them from simplest to most complex:
+
+=over 4
+
+=item * absolute timer (offset = absolute time, interval = 0, reschedule_cb = 0)
+
+In this configuration the watcher triggers an event after the wall clock
+time C<offset> has passed. It will not repeat and will not adjust when a
+time jump occurs, that is, if it is to be run at January 1st 2011 then it
+will be stopped and invoked when the system clock reaches or surpasses
+this point in time.
+
+=item * repeating interval timer (offset = offset within interval, interval > 0, reschedule_cb = 0)
+
+In this mode the watcher will always be scheduled to time out at the next
+C<offset + N * interval> time (for some integer N, which can also be
+negative) and then repeat, regardless of any time jumps. The C<offset>
+argument is merely an offset into the C<interval> periods.
+
+This can be used to create timers that do not drift with respect to the
+system clock, for example, here is an C<ev_periodic> that triggers each
+hour, on the hour (with respect to UTC):
+
+ ev_periodic_set (&periodic, 0., 3600., 0);
+
+This doesn't mean there will always be 3600 seconds in between triggers,
+but only that the callback will be called when the system time shows a
+full hour (UTC), or more correctly, when the system time is evenly divisible
+by 3600.
+
+Another way to think about it (for the mathematically inclined) is that
+C<ev_periodic> will try to run the callback in this mode at the next possible
+time where C<time = offset (mod interval)>, regardless of any time jumps.
+
+The C<interval> I<MUST> be positive, and for numerical stability, the
+interval value should be higher than C<1/8192> (which is around 100
+microseconds) and C<offset> should be higher than C<0> and should have
+at most a similar magnitude as the current time (say, within a factor of
+ten). Typical values for offset are, in fact, C<0> or something between
+C<0> and C<interval>, which is also the recommended range.
+
+Note also that there is an upper limit to how often a timer can fire (CPU
+speed for example), so if C<interval> is very small then timing stability
+will of course deteriorate. Libev itself tries to be exact to be about one
+millisecond (if the OS supports it and the machine is fast enough).
+
+=item * manual reschedule mode (offset ignored, interval ignored, reschedule_cb = callback)
+
+In this mode the values for C<interval> and C<offset> are both being
+ignored. Instead, each time the periodic watcher gets scheduled, the
+reschedule callback will be called with the watcher as first, and the
+current time as second argument.
+
+NOTE: I<This callback MUST NOT stop or destroy any periodic watcher, ever,
+or make ANY other event loop modifications whatsoever, unless explicitly
+allowed by documentation here>.
+
+If you need to stop it, return C<now + 1e30> (or so, fudge fudge) and stop
+it afterwards (e.g. by starting an C<ev_prepare> watcher, which is the
+only event loop modification you are allowed to do).
+
+The callback prototype is C<ev_tstamp (*reschedule_cb)(ev_periodic
+*w, ev_tstamp now)>, e.g.:
+
+ static ev_tstamp
+ my_rescheduler (ev_periodic *w, ev_tstamp now)
+ {
+ return now + 60.;
+ }
+
+It must return the next time to trigger, based on the passed time value
+(that is, the lowest time value larger than to the second argument). It
+will usually be called just before the callback will be triggered, but
+might be called at other times, too.
+
+NOTE: I<< This callback must always return a time that is higher than or
+equal to the passed C<now> value >>.
+
+This can be used to create very complex timers, such as a timer that
+triggers on "next midnight, local time". To do this, you would calculate the
+next midnight after C<now> and return the timestamp value for this. How
+you do this is, again, up to you (but it is not trivial, which is the main
+reason I omitted it as an example).
+
+=back
+
+=item ev_periodic_again (loop, ev_periodic *)
+
+Simply stops and restarts the periodic watcher again. This is only useful
+when you changed some parameters or the reschedule callback would return
+a different time than the last time it was called (e.g. in a crond like
+program when the crontabs have changed).
+
+=item ev_tstamp ev_periodic_at (ev_periodic *)
+
+When active, returns the absolute time that the watcher is supposed
+to trigger next. This is not the same as the C<offset> argument to
+C<ev_periodic_set>, but indeed works even in interval and manual
+rescheduling modes.
+
+=item ev_tstamp offset [read-write]
+
+When repeating, this contains the offset value, otherwise this is the
+absolute point in time (the C<offset> value passed to C<ev_periodic_set>,
+although libev might modify this value for better numerical stability).
+
+Can be modified any time, but changes only take effect when the periodic
+timer fires or C<ev_periodic_again> is being called.
+
+=item ev_tstamp interval [read-write]
+
+The current interval value. Can be modified any time, but changes only
+take effect when the periodic timer fires or C<ev_periodic_again> is being
+called.
+
+=item ev_tstamp (*reschedule_cb)(ev_periodic *w, ev_tstamp now) [read-write]
+
+The current reschedule callback, or C<0>, if this functionality is
+switched off. Can be changed any time, but changes only take effect when
+the periodic timer fires or C<ev_periodic_again> is being called.
+
+=back
+
+=head3 Examples
+
+Example: Call a callback every hour, or, more precisely, whenever the
+system time is divisible by 3600. The callback invocation times have
+potentially a lot of jitter, but good long-term stability.
+
+ static void
+ clock_cb (struct ev_loop *loop, ev_periodic *w, int revents)
+ {
+ ... its now a full hour (UTC, or TAI or whatever your clock follows)
+ }
+
+ ev_periodic hourly_tick;
+ ev_periodic_init (&hourly_tick, clock_cb, 0., 3600., 0);
+ ev_periodic_start (loop, &hourly_tick);
+
+Example: The same as above, but use a reschedule callback to do it:
+
+ #include <math.h>
+
+ static ev_tstamp
+ my_scheduler_cb (ev_periodic *w, ev_tstamp now)
+ {
+ return now + (3600. - fmod (now, 3600.));
+ }
+
+ ev_periodic_init (&hourly_tick, clock_cb, 0., 0., my_scheduler_cb);
+
+Example: Call a callback every hour, starting now:
+
+ ev_periodic hourly_tick;
+ ev_periodic_init (&hourly_tick, clock_cb,
+ fmod (ev_now (loop), 3600.), 3600., 0);
+ ev_periodic_start (loop, &hourly_tick);
+
+
+=head2 C<ev_signal> - signal me when a signal gets signalled!
+
+Signal watchers will trigger an event when the process receives a specific
+signal one or more times. Even though signals are very asynchronous, libev
+will try its best to deliver signals synchronously, i.e. as part of the
+normal event processing, like any other event.
+
+If you want signals to be delivered truly asynchronously, just use
+C<sigaction> as you would do without libev and forget about sharing
+the signal. You can even use C<ev_async> from a signal handler to
+synchronously wake up an event loop.
+
+You can configure as many watchers as you like for the same signal, but
+only within the same loop, i.e. you can watch for C<SIGINT> in your
+default loop and for C<SIGIO> in another loop, but you cannot watch for
+C<SIGINT> in both the default loop and another loop at the same time. At
+the moment, C<SIGCHLD> is permanently tied to the default loop.
+
+Only after the first watcher for a signal is started will libev actually
+register something with the kernel. It thus coexists with your own signal
+handlers as long as you don't register any with libev for the same signal.
+
+If possible and supported, libev will install its handlers with
+C<SA_RESTART> (or equivalent) behaviour enabled, so system calls should
+not be unduly interrupted. If you have a problem with system calls getting
+interrupted by signals you can block all signals in an C<ev_check> watcher
+and unblock them in an C<ev_prepare> watcher.
+
+=head3 The special problem of inheritance over fork/execve/pthread_create
+
+Both the signal mask (C<sigprocmask>) and the signal disposition
+(C<sigaction>) are unspecified after starting a signal watcher (and after
+stopping it again), that is, libev might or might not block the signal,
+and might or might not set or restore the installed signal handler (but
+see C<EVFLAG_NOSIGMASK>).
+
+While this does not matter for the signal disposition (libev never
+sets signals to C<SIG_IGN>, so handlers will be reset to C<SIG_DFL> on
+C<execve>), this matters for the signal mask: many programs do not expect
+certain signals to be blocked.
+
+This means that before calling C<exec> (from the child) you should reset
+the signal mask to whatever "default" you expect (all clear is a good
+choice usually).
+
+The simplest way to ensure that the signal mask is reset in the child is
+to install a fork handler with C<pthread_atfork> that resets it. That will
+catch fork calls done by libraries (such as the libc) as well.
+
+In current versions of libev, the signal will not be blocked indefinitely
+unless you use the C<signalfd> API (C<EV_SIGNALFD>). While this reduces
+the window of opportunity for problems, it will not go away, as libev
+I<has> to modify the signal mask, at least temporarily.
+
+So I can't stress this enough: I<If you do not reset your signal mask when
+you expect it to be empty, you have a race condition in your code>. This
+is not a libev-specific thing, this is true for most event libraries.
+
+=head3 The special problem of threads signal handling
+
+POSIX threads has problematic signal handling semantics, specifically,
+a lot of functionality (sigfd, sigwait etc.) only really works if all
+threads in a process block signals, which is hard to achieve.
+
+When you want to use sigwait (or mix libev signal handling with your own
+for the same signals), you can tackle this problem by globally blocking
+all signals before creating any threads (or creating them with a fully set
+sigprocmask) and also specifying the C<EVFLAG_NOSIGMASK> when creating
+loops. Then designate one thread as "signal receiver thread" which handles
+these signals. You can pass on any signals that libev might be interested
+in by calling C<ev_feed_signal>.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_signal_init (ev_signal *, callback, int signum)
+
+=item ev_signal_set (ev_signal *, int signum)
+
+Configures the watcher to trigger on the given signal number (usually one
+of the C<SIGxxx> constants).
+
+=item int signum [read-only]
+
+The signal the watcher watches out for.
+
+=back
+
+=head3 Examples
+
+Example: Try to exit cleanly on SIGINT.
+
+ static void
+ sigint_cb (struct ev_loop *loop, ev_signal *w, int revents)
+ {
+ ev_break (loop, EVBREAK_ALL);
+ }
+
+ ev_signal signal_watcher;
+ ev_signal_init (&signal_watcher, sigint_cb, SIGINT);
+ ev_signal_start (loop, &signal_watcher);
+
+
+=head2 C<ev_child> - watch out for process status changes
+
+Child watchers trigger when your process receives a SIGCHLD in response to
+some child status changes (most typically when a child of yours dies or
+exits). It is permissible to install a child watcher I<after> the child
+has been forked (which implies it might have already exited), as long
+as the event loop isn't entered (or is continued from a watcher), i.e.,
+forking and then immediately registering a watcher for the child is fine,
+but forking and registering a watcher a few event loop iterations later or
+in the next callback invocation is not.
+
+Only the default event loop is capable of handling signals, and therefore
+you can only register child watchers in the default event loop.
+
+Due to some design glitches inside libev, child watchers will always be
+handled at maximum priority (their priority is set to C<EV_MAXPRI> by
+libev)
+
+=head3 Process Interaction
+
+Libev grabs C<SIGCHLD> as soon as the default event loop is
+initialised. This is necessary to guarantee proper behaviour even if the
+first child watcher is started after the child exits. The occurrence
+of C<SIGCHLD> is recorded asynchronously, but child reaping is done
+synchronously as part of the event loop processing. Libev always reaps all
+children, even ones not watched.
+
+=head3 Overriding the Built-In Processing
+
+Libev offers no special support for overriding the built-in child
+processing, but if your application collides with libev's default child
+handler, you can override it easily by installing your own handler for
+C<SIGCHLD> after initialising the default loop, and making sure the
+default loop never gets destroyed. You are encouraged, however, to use an
+event-based approach to child reaping and thus use libev's support for
+that, so other libev users can use C<ev_child> watchers freely.
+
+=head3 Stopping the Child Watcher
+
+Currently, the child watcher never gets stopped, even when the
+child terminates, so normally one needs to stop the watcher in the
+callback. Future versions of libev might stop the watcher automatically
+when a child exit is detected (calling C<ev_child_stop> twice is not a
+problem).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_child_init (ev_child *, callback, int pid, int trace)
+
+=item ev_child_set (ev_child *, int pid, int trace)
+
+Configures the watcher to wait for status changes of process C<pid> (or
+I<any> process if C<pid> is specified as C<0>). The callback can look
+at the C<rstatus> member of the C<ev_child> watcher structure to see
+the status word (use the macros from C<sys/wait.h> and see your systems
+C<waitpid> documentation). The C<rpid> member contains the pid of the
+process causing the status change. C<trace> must be either C<0> (only
+activate the watcher when the process terminates) or C<1> (additionally
+activate the watcher when the process is stopped or continued).
+
+=item int pid [read-only]
+
+The process id this watcher watches out for, or C<0>, meaning any process id.
+
+=item int rpid [read-write]
+
+The process id that detected a status change.
+
+=item int rstatus [read-write]
+
+The process exit/trace status caused by C<rpid> (see your systems
+C<waitpid> and C<sys/wait.h> documentation for details).
+
+=back
+
+=head3 Examples
+
+Example: C<fork()> a new process and install a child handler to wait for
+its completion.
+
+ ev_child cw;
+
+ static void
+ child_cb (EV_P_ ev_child *w, int revents)
+ {
+ ev_child_stop (EV_A_ w);
+ printf ("process %d exited with status %x\n", w->rpid, w->rstatus);
+ }
+
+ pid_t pid = fork ();
+
+ if (pid < 0)
+ // error
+ else if (pid == 0)
+ {
+ // the forked child executes here
+ exit (1);
+ }
+ else
+ {
+ ev_child_init (&cw, child_cb, pid, 0);
+ ev_child_start (EV_DEFAULT_ &cw);
+ }
+
+
+=head2 C<ev_stat> - did the file attributes just change?
+
+This watches a file system path for attribute changes. That is, it calls
+C<stat> on that path in regular intervals (or when the OS says it changed)
+and sees if it changed compared to the last time, invoking the callback
+if it did. Starting the watcher C<stat>'s the file, so only changes that
+happen after the watcher has been started will be reported.
+
+The path does not need to exist: changing from "path exists" to "path does
+not exist" is a status change like any other. The condition "path does not
+exist" (or more correctly "path cannot be stat'ed") is signified by the
+C<st_nlink> field being zero (which is otherwise always forced to be at
+least one) and all the other fields of the stat buffer having unspecified
+contents.
+
+The path I<must not> end in a slash or contain special components such as
+C<.> or C<..>. The path I<should> be absolute: If it is relative and
+your working directory changes, then the behaviour is undefined.
+
+Since there is no portable change notification interface available, the
+portable implementation simply calls C<stat(2)> regularly on the path
+to see if it changed somehow. You can specify a recommended polling
+interval for this case. If you specify a polling interval of C<0> (highly
+recommended!) then a I<suitable, unspecified default> value will be used
+(which you can expect to be around five seconds, although this might
+change dynamically). Libev will also impose a minimum interval which is
+currently around C<0.1>, but that's usually overkill.
+
+This watcher type is not meant for massive numbers of stat watchers,
+as even with OS-supported change notifications, this can be
+resource-intensive.
+
+At the time of this writing, the only OS-specific interface implemented
+is the Linux inotify interface (implementing kqueue support is left as an
+exercise for the reader. Note, however, that the author sees no way of
+implementing C<ev_stat> semantics with kqueue, except as a hint).
+
+=head3 ABI Issues (Largefile Support)
+
+Libev by default (unless the user overrides this) uses the default
+compilation environment, which means that on systems with large file
+support disabled by default, you get the 32 bit version of the stat
+structure. When using the library from programs that change the ABI to
+use 64 bit file offsets the programs will fail. In that case you have to
+compile libev with the same flags to get binary compatibility. This is
+obviously the case with any flags that change the ABI, but the problem is
+most noticeably displayed with ev_stat and large file support.
+
+The solution for this is to lobby your distribution maker to make large
+file interfaces available by default (as e.g. FreeBSD does) and not
+optional. Libev cannot simply switch on large file support because it has
+to exchange stat structures with application programs compiled using the
+default compilation environment.
+
+=head3 Inotify and Kqueue
+
+When C<inotify (7)> support has been compiled into libev and present at
+runtime, it will be used to speed up change detection where possible. The
+inotify descriptor will be created lazily when the first C<ev_stat>
+watcher is being started.
+
+Inotify presence does not change the semantics of C<ev_stat> watchers
+except that changes might be detected earlier, and in some cases, to avoid
+making regular C<stat> calls. Even in the presence of inotify support
+there are many cases where libev has to resort to regular C<stat> polling,
+but as long as kernel 2.6.25 or newer is used (2.6.24 and older have too
+many bugs), the path exists (i.e. stat succeeds), and the path resides on
+a local filesystem (libev currently assumes only ext2/3, jfs, reiserfs and
+xfs are fully working) libev usually gets away without polling.
+
+There is no support for kqueue, as apparently it cannot be used to
+implement this functionality, due to the requirement of having a file
+descriptor open on the object at all times, and detecting renames, unlinks
+etc. is difficult.
+
+=head3 C<stat ()> is a synchronous operation
+
+Libev doesn't normally do any kind of I/O itself, and so is not blocking
+the process. The exception are C<ev_stat> watchers - those call C<stat
+()>, which is a synchronous operation.
+
+For local paths, this usually doesn't matter: unless the system is very
+busy or the intervals between stat's are large, a stat call will be fast,
+as the path data is usually in memory already (except when starting the
+watcher).
+
+For networked file systems, calling C<stat ()> can block an indefinite
+time due to network issues, and even under good conditions, a stat call
+often takes multiple milliseconds.
+
+Therefore, it is best to avoid using C<ev_stat> watchers on networked
+paths, although this is fully supported by libev.
+
+=head3 The special problem of stat time resolution
+
+The C<stat ()> system call only supports full-second resolution portably,
+and even on systems where the resolution is higher, most file systems
+still only support whole seconds.
+
+That means that, if the time is the only thing that changes, you can
+easily miss updates: on the first update, C<ev_stat> detects a change and
+calls your callback, which does something. When there is another update
+within the same second, C<ev_stat> will be unable to detect unless the
+stat data does change in other ways (e.g. file size).
+
+The solution to this is to delay acting on a change for slightly more
+than a second (or till slightly after the next full second boundary), using
+a roughly one-second-delay C<ev_timer> (e.g. C<ev_timer_set (w, 0., 1.02);
+ev_timer_again (loop, w)>).
+
+The C<.02> offset is added to work around small timing inconsistencies
+of some operating systems (where the second counter of the current time
+might be be delayed. One such system is the Linux kernel, where a call to
+C<gettimeofday> might return a timestamp with a full second later than
+a subsequent C<time> call - if the equivalent of C<time ()> is used to
+update file times then there will be a small window where the kernel uses
+the previous second to update file times but libev might already execute
+the timer callback).
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_stat_init (ev_stat *, callback, const char *path, ev_tstamp interval)
+
+=item ev_stat_set (ev_stat *, const char *path, ev_tstamp interval)
+
+Configures the watcher to wait for status changes of the given
+C<path>. The C<interval> is a hint on how quickly a change is expected to
+be detected and should normally be specified as C<0> to let libev choose
+a suitable value. The memory pointed to by C<path> must point to the same
+path for as long as the watcher is active.
+
+The callback will receive an C<EV_STAT> event when a change was detected,
+relative to the attributes at the time the watcher was started (or the
+last change was detected).
+
+=item ev_stat_stat (loop, ev_stat *)
+
+Updates the stat buffer immediately with new values. If you change the
+watched path in your callback, you could call this function to avoid
+detecting this change (while introducing a race condition if you are not
+the only one changing the path). Can also be useful simply to find out the
+new values.
+
+=item ev_statdata attr [read-only]
+
+The most-recently detected attributes of the file. Although the type is
+C<ev_statdata>, this is usually the (or one of the) C<struct stat> types
+suitable for your system, but you can only rely on the POSIX-standardised
+members to be present. If the C<st_nlink> member is C<0>, then there was
+some error while C<stat>ing the file.
+
+=item ev_statdata prev [read-only]
+
+The previous attributes of the file. The callback gets invoked whenever
+C<prev> != C<attr>, or, more precisely, one or more of these members
+differ: C<st_dev>, C<st_ino>, C<st_mode>, C<st_nlink>, C<st_uid>,
+C<st_gid>, C<st_rdev>, C<st_size>, C<st_atime>, C<st_mtime>, C<st_ctime>.
+
+=item ev_tstamp interval [read-only]
+
+The specified interval.
+
+=item const char *path [read-only]
+
+The file system path that is being watched.
+
+=back
+
+=head3 Examples
+
+Example: Watch C</etc/passwd> for attribute changes.
+
+ static void
+ passwd_cb (struct ev_loop *loop, ev_stat *w, int revents)
+ {
+ /* /etc/passwd changed in some way */
+ if (w->attr.st_nlink)
+ {
+ printf ("passwd current size %ld\n", (long)w->attr.st_size);
+ printf ("passwd current atime %ld\n", (long)w->attr.st_mtime);
+ printf ("passwd current mtime %ld\n", (long)w->attr.st_mtime);
+ }
+ else
+ /* you shalt not abuse printf for puts */
+ puts ("wow, /etc/passwd is not there, expect problems. "
+ "if this is windows, they already arrived\n");
+ }
+
+ ...
+ ev_stat passwd;
+
+ ev_stat_init (&passwd, passwd_cb, "/etc/passwd", 0.);
+ ev_stat_start (loop, &passwd);
+
+Example: Like above, but additionally use a one-second delay so we do not
+miss updates (however, frequent updates will delay processing, too, so
+one might do the work both on C<ev_stat> callback invocation I<and> on
+C<ev_timer> callback invocation).
+
+ static ev_stat passwd;
+ static ev_timer timer;
+
+ static void
+ timer_cb (EV_P_ ev_timer *w, int revents)
+ {
+ ev_timer_stop (EV_A_ w);
+
+ /* now it's one second after the most recent passwd change */
+ }
+
+ static void
+ stat_cb (EV_P_ ev_stat *w, int revents)
+ {
+ /* reset the one-second timer */
+ ev_timer_again (EV_A_ &timer);
+ }
+
+ ...
+ ev_stat_init (&passwd, stat_cb, "/etc/passwd", 0.);
+ ev_stat_start (loop, &passwd);
+ ev_timer_init (&timer, timer_cb, 0., 1.02);
+
+
+=head2 C<ev_idle> - when you've got nothing better to do...
+
+Idle watchers trigger events when no other events of the same or higher
+priority are pending (prepare, check and other idle watchers do not count
+as receiving "events").
+
+That is, as long as your process is busy handling sockets or timeouts
+(or even signals, imagine) of the same or higher priority it will not be
+triggered. But when your process is idle (or only lower-priority watchers
+are pending), the idle watchers are being called once per event loop
+iteration - until stopped, that is, or your process receives more events
+and becomes busy again with higher priority stuff.
+
+The most noteworthy effect is that as long as any idle watchers are
+active, the process will not block when waiting for new events.
+
+Apart from keeping your process non-blocking (which is a useful
+effect on its own sometimes), idle watchers are a good place to do
+"pseudo-background processing", or delay processing stuff to after the
+event loop has handled all outstanding events.
+
+=head3 Abusing an C<ev_idle> watcher for its side-effect
+
+As long as there is at least one active idle watcher, libev will never
+sleep unnecessarily. Or in other words, it will loop as fast as possible.
+For this to work, the idle watcher doesn't need to be invoked at all - the
+lowest priority will do.
+
+This mode of operation can be useful together with an C<ev_check> watcher,
+to do something on each event loop iteration - for example to balance load
+between different connections.
+
+See L</Abusing an ev_check watcher for its side-effect> for a longer
+example.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_idle_init (ev_idle *, callback)
+
+Initialises and configures the idle watcher - it has no parameters of any
+kind. There is a C<ev_idle_set> macro, but using it is utterly pointless,
+believe me.
+
+=back
+
+=head3 Examples
+
+Example: Dynamically allocate an C<ev_idle> watcher, start it, and in the
+callback, free it. Also, use no error checking, as usual.
+
+ static void
+ idle_cb (struct ev_loop *loop, ev_idle *w, int revents)
+ {
+ // stop the watcher
+ ev_idle_stop (loop, w);
+
+ // now we can free it
+ free (w);
+
+ // now do something you wanted to do when the program has
+ // no longer anything immediate to do.
+ }
+
+ ev_idle *idle_watcher = malloc (sizeof (ev_idle));
+ ev_idle_init (idle_watcher, idle_cb);
+ ev_idle_start (loop, idle_watcher);
+
+
+=head2 C<ev_prepare> and C<ev_check> - customise your event loop!
+
+Prepare and check watchers are often (but not always) used in pairs:
+prepare watchers get invoked before the process blocks and check watchers
+afterwards.
+
+You I<must not> call C<ev_run> (or similar functions that enter the
+current event loop) or C<ev_loop_fork> from either C<ev_prepare> or
+C<ev_check> watchers. Other loops than the current one are fine,
+however. The rationale behind this is that you do not need to check
+for recursion in those watchers, i.e. the sequence will always be
+C<ev_prepare>, blocking, C<ev_check> so if you have one watcher of each
+kind they will always be called in pairs bracketing the blocking call.
+
+Their main purpose is to integrate other event mechanisms into libev and
+their use is somewhat advanced. They could be used, for example, to track
+variable changes, implement your own watchers, integrate net-snmp or a
+coroutine library and lots more. They are also occasionally useful if
+you cache some data and want to flush it before blocking (for example,
+in X programs you might want to do an C<XFlush ()> in an C<ev_prepare>
+watcher).
+
+This is done by examining in each prepare call which file descriptors
+need to be watched by the other library, registering C<ev_io> watchers
+for them and starting an C<ev_timer> watcher for any timeouts (many
+libraries provide exactly this functionality). Then, in the check watcher,
+you check for any events that occurred (by checking the pending status
+of all watchers and stopping them) and call back into the library. The
+I/O and timer callbacks will never actually be called (but must be valid
+nevertheless, because you never know, you know?).
+
+As another example, the Perl Coro module uses these hooks to integrate
+coroutines into libev programs, by yielding to other active coroutines
+during each prepare and only letting the process block if no coroutines
+are ready to run (it's actually more complicated: it only runs coroutines
+with priority higher than or equal to the event loop and one coroutine
+of lower priority, but only once, using idle watchers to keep the event
+loop from blocking if lower-priority coroutines are active, thus mapping
+low-priority coroutines to idle/background tasks).
+
+When used for this purpose, it is recommended to give C<ev_check> watchers
+highest (C<EV_MAXPRI>) priority, to ensure that they are being run before
+any other watchers after the poll (this doesn't matter for C<ev_prepare>
+watchers).
+
+Also, C<ev_check> watchers (and C<ev_prepare> watchers, too) should not
+activate ("feed") events into libev. While libev fully supports this, they
+might get executed before other C<ev_check> watchers did their job. As
+C<ev_check> watchers are often used to embed other (non-libev) event
+loops those other event loops might be in an unusable state until their
+C<ev_check> watcher ran (always remind yourself to coexist peacefully with
+others).
+
+=head3 Abusing an C<ev_check> watcher for its side-effect
+
+C<ev_check> (and less often also C<ev_prepare>) watchers can also be
+useful because they are called once per event loop iteration. For
+example, if you want to handle a large number of connections fairly, you
+normally only do a bit of work for each active connection, and if there
+is more work to do, you wait for the next event loop iteration, so other
+connections have a chance of making progress.
+
+Using an C<ev_check> watcher is almost enough: it will be called on the
+next event loop iteration. However, that isn't as soon as possible -
+without external events, your C<ev_check> watcher will not be invoked.
+
+This is where C<ev_idle> watchers come in handy - all you need is a
+single global idle watcher that is active as long as you have one active
+C<ev_check> watcher. The C<ev_idle> watcher makes sure the event loop
+will not sleep, and the C<ev_check> watcher makes sure a callback gets
+invoked. Neither watcher alone can do that.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_prepare_init (ev_prepare *, callback)
+
+=item ev_check_init (ev_check *, callback)
+
+Initialises and configures the prepare or check watcher - they have no
+parameters of any kind. There are C<ev_prepare_set> and C<ev_check_set>
+macros, but using them is utterly, utterly, utterly and completely
+pointless.
+
+=back
+
+=head3 Examples
+
+There are a number of principal ways to embed other event loops or modules
+into libev. Here are some ideas on how to include libadns into libev
+(there is a Perl module named C<EV::ADNS> that does this, which you could
+use as a working example. Another Perl module named C<EV::Glib> embeds a
+Glib main context into libev, and finally, C<Glib::EV> embeds EV into the
+Glib event loop).
+
+Method 1: Add IO watchers and a timeout watcher in a prepare handler,
+and in a check watcher, destroy them and call into libadns. What follows
+is pseudo-code only of course. This requires you to either use a low
+priority for the check watcher or use C<ev_clear_pending> explicitly, as
+the callbacks for the IO/timeout watchers might not have been called yet.
+
+ static ev_io iow [nfd];
+ static ev_timer tw;
+
+ static void
+ io_cb (struct ev_loop *loop, ev_io *w, int revents)
+ {
+ }
+
+ // create io watchers for each fd and a timer before blocking
+ static void
+ adns_prepare_cb (struct ev_loop *loop, ev_prepare *w, int revents)
+ {
+ int timeout = 3600000;
+ struct pollfd fds [nfd];
+ // actual code will need to loop here and realloc etc.
+ adns_beforepoll (ads, fds, &nfd, &timeout, timeval_from (ev_time ()));
+
+ /* the callback is illegal, but won't be called as we stop during check */
+ ev_timer_init (&tw, 0, timeout * 1e-3, 0.);
+ ev_timer_start (loop, &tw);
+
+ // create one ev_io per pollfd
+ for (int i = 0; i < nfd; ++i)
+ {
+ ev_io_init (iow + i, io_cb, fds [i].fd,
+ ((fds [i].events & POLLIN ? EV_READ : 0)
+ | (fds [i].events & POLLOUT ? EV_WRITE : 0)));
+
+ fds [i].revents = 0;
+ ev_io_start (loop, iow + i);
+ }
+ }
+
+ // stop all watchers after blocking
+ static void
+ adns_check_cb (struct ev_loop *loop, ev_check *w, int revents)
+ {
+ ev_timer_stop (loop, &tw);
+
+ for (int i = 0; i < nfd; ++i)
+ {
+ // set the relevant poll flags
+ // could also call adns_processreadable etc. here
+ struct pollfd *fd = fds + i;
+ int revents = ev_clear_pending (iow + i);
+ if (revents & EV_READ ) fd->revents |= fd->events & POLLIN;
+ if (revents & EV_WRITE) fd->revents |= fd->events & POLLOUT;
+
+ // now stop the watcher
+ ev_io_stop (loop, iow + i);
+ }
+
+ adns_afterpoll (adns, fds, nfd, timeval_from (ev_now (loop));
+ }
+
+Method 2: This would be just like method 1, but you run C<adns_afterpoll>
+in the prepare watcher and would dispose of the check watcher.
+
+Method 3: If the module to be embedded supports explicit event
+notification (libadns does), you can also make use of the actual watcher
+callbacks, and only destroy/create the watchers in the prepare watcher.
+
+ static void
+ timer_cb (EV_P_ ev_timer *w, int revents)
+ {
+ adns_state ads = (adns_state)w->data;
+ update_now (EV_A);
+
+ adns_processtimeouts (ads, &tv_now);
+ }
+
+ static void
+ io_cb (EV_P_ ev_io *w, int revents)
+ {
+ adns_state ads = (adns_state)w->data;
+ update_now (EV_A);
+
+ if (revents & EV_READ ) adns_processreadable (ads, w->fd, &tv_now);
+ if (revents & EV_WRITE) adns_processwriteable (ads, w->fd, &tv_now);
+ }
+
+ // do not ever call adns_afterpoll
+
+Method 4: Do not use a prepare or check watcher because the module you
+want to embed is not flexible enough to support it. Instead, you can
+override their poll function. The drawback with this solution is that the
+main loop is now no longer controllable by EV. The C<Glib::EV> module uses
+this approach, effectively embedding EV as a client into the horrible
+libglib event loop.
+
+ static gint
+ event_poll_func (GPollFD *fds, guint nfds, gint timeout)
+ {
+ int got_events = 0;
+
+ for (n = 0; n < nfds; ++n)
+ // create/start io watcher that sets the relevant bits in fds[n] and increment got_events
+
+ if (timeout >= 0)
+ // create/start timer
+
+ // poll
+ ev_run (EV_A_ 0);
+
+ // stop timer again
+ if (timeout >= 0)
+ ev_timer_stop (EV_A_ &to);
+
+ // stop io watchers again - their callbacks should have set
+ for (n = 0; n < nfds; ++n)
+ ev_io_stop (EV_A_ iow [n]);
+
+ return got_events;
+ }
+
+
+=head2 C<ev_embed> - when one backend isn't enough...
+
+This is a rather advanced watcher type that lets you embed one event loop
+into another (currently only C<ev_io> events are supported in the embedded
+loop, other types of watchers might be handled in a delayed or incorrect
+fashion and must not be used).
+
+There are primarily two reasons you would want that: work around bugs and
+prioritise I/O.
+
+As an example for a bug workaround, the kqueue backend might only support
+sockets on some platform, so it is unusable as generic backend, but you
+still want to make use of it because you have many sockets and it scales
+so nicely. In this case, you would create a kqueue-based loop and embed
+it into your default loop (which might use e.g. poll). Overall operation
+will be a bit slower because first libev has to call C<poll> and then
+C<kevent>, but at least you can use both mechanisms for what they are
+best: C<kqueue> for scalable sockets and C<poll> if you want it to work :)
+
+As for prioritising I/O: under rare circumstances you have the case where
+some fds have to be watched and handled very quickly (with low latency),
+and even priorities and idle watchers might have too much overhead. In
+this case you would put all the high priority stuff in one loop and all
+the rest in a second one, and embed the second one in the first.
+
+As long as the watcher is active, the callback will be invoked every
+time there might be events pending in the embedded loop. The callback
+must then call C<ev_embed_sweep (mainloop, watcher)> to make a single
+sweep and invoke their callbacks (the callback doesn't need to invoke the
+C<ev_embed_sweep> function directly, it could also start an idle watcher
+to give the embedded loop strictly lower priority for example).
+
+You can also set the callback to C<0>, in which case the embed watcher
+will automatically execute the embedded loop sweep whenever necessary.
+
+Fork detection will be handled transparently while the C<ev_embed> watcher
+is active, i.e., the embedded loop will automatically be forked when the
+embedding loop forks. In other cases, the user is responsible for calling
+C<ev_loop_fork> on the embedded loop.
+
+Unfortunately, not all backends are embeddable: only the ones returned by
+C<ev_embeddable_backends> are, which, unfortunately, does not include any
+portable one.
+
+So when you want to use this feature you will always have to be prepared
+that you cannot get an embeddable loop. The recommended way to get around
+this is to have a separate variables for your embeddable loop, try to
+create it, and if that fails, use the normal loop for everything.
+
+=head3 C<ev_embed> and fork
+
+While the C<ev_embed> watcher is running, forks in the embedding loop will
+automatically be applied to the embedded loop as well, so no special
+fork handling is required in that case. When the watcher is not running,
+however, it is still the task of the libev user to call C<ev_loop_fork ()>
+as applicable.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_embed_init (ev_embed *, callback, struct ev_loop *embedded_loop)
+
+=item ev_embed_set (ev_embed *, struct ev_loop *embedded_loop)
+
+Configures the watcher to embed the given loop, which must be
+embeddable. If the callback is C<0>, then C<ev_embed_sweep> will be
+invoked automatically, otherwise it is the responsibility of the callback
+to invoke it (it will continue to be called until the sweep has been done,
+if you do not want that, you need to temporarily stop the embed watcher).
+
+=item ev_embed_sweep (loop, ev_embed *)
+
+Make a single, non-blocking sweep over the embedded loop. This works
+similarly to C<ev_run (embedded_loop, EVRUN_NOWAIT)>, but in the most
+appropriate way for embedded loops.
+
+=item struct ev_loop *other [read-only]
+
+The embedded event loop.
+
+=back
+
+=head3 Examples
+
+Example: Try to get an embeddable event loop and embed it into the default
+event loop. If that is not possible, use the default loop. The default
+loop is stored in C<loop_hi>, while the embeddable loop is stored in
+C<loop_lo> (which is C<loop_hi> in the case no embeddable loop can be
+used).
+
+ struct ev_loop *loop_hi = ev_default_init (0);
+ struct ev_loop *loop_lo = 0;
+ ev_embed embed;
+
+ // see if there is a chance of getting one that works
+ // (remember that a flags value of 0 means autodetection)
+ loop_lo = ev_embeddable_backends () & ev_recommended_backends ()
+ ? ev_loop_new (ev_embeddable_backends () & ev_recommended_backends ())
+ : 0;
+
+ // if we got one, then embed it, otherwise default to loop_hi
+ if (loop_lo)
+ {
+ ev_embed_init (&embed, 0, loop_lo);
+ ev_embed_start (loop_hi, &embed);
+ }
+ else
+ loop_lo = loop_hi;
+
+Example: Check if kqueue is available but not recommended and create
+a kqueue backend for use with sockets (which usually work with any
+kqueue implementation). Store the kqueue/socket-only event loop in
+C<loop_socket>. (One might optionally use C<EVFLAG_NOENV>, too).
+
+ struct ev_loop *loop = ev_default_init (0);
+ struct ev_loop *loop_socket = 0;
+ ev_embed embed;
+
+ if (ev_supported_backends () & ~ev_recommended_backends () & EVBACKEND_KQUEUE)
+ if ((loop_socket = ev_loop_new (EVBACKEND_KQUEUE))
+ {
+ ev_embed_init (&embed, 0, loop_socket);
+ ev_embed_start (loop, &embed);
+ }
+
+ if (!loop_socket)
+ loop_socket = loop;
+
+ // now use loop_socket for all sockets, and loop for everything else
+
+
+=head2 C<ev_fork> - the audacity to resume the event loop after a fork
+
+Fork watchers are called when a C<fork ()> was detected (usually because
+whoever is a good citizen cared to tell libev about it by calling
+C<ev_loop_fork>). The invocation is done before the event loop blocks next
+and before C<ev_check> watchers are being called, and only in the child
+after the fork. If whoever good citizen calling C<ev_default_fork> cheats
+and calls it in the wrong process, the fork handlers will be invoked, too,
+of course.
+
+=head3 The special problem of life after fork - how is it possible?
+
+Most uses of C<fork ()> consist of forking, then some simple calls to set
+up/change the process environment, followed by a call to C<exec()>. This
+sequence should be handled by libev without any problems.
+
+This changes when the application actually wants to do event handling
+in the child, or both parent in child, in effect "continuing" after the
+fork.
+
+The default mode of operation (for libev, with application help to detect
+forks) is to duplicate all the state in the child, as would be expected
+when I<either> the parent I<or> the child process continues.
+
+When both processes want to continue using libev, then this is usually the
+wrong result. In that case, usually one process (typically the parent) is
+supposed to continue with all watchers in place as before, while the other
+process typically wants to start fresh, i.e. without any active watchers.
+
+The cleanest and most efficient way to achieve that with libev is to
+simply create a new event loop, which of course will be "empty", and
+use that for new watchers. This has the advantage of not touching more
+memory than necessary, and thus avoiding the copy-on-write, and the
+disadvantage of having to use multiple event loops (which do not support
+signal watchers).
+
+When this is not possible, or you want to use the default loop for
+other reasons, then in the process that wants to start "fresh", call
+C<ev_loop_destroy (EV_DEFAULT)> followed by C<ev_default_loop (...)>.
+Destroying the default loop will "orphan" (not stop) all registered
+watchers, so you have to be careful not to execute code that modifies
+those watchers. Note also that in that case, you have to re-register any
+signal watchers.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_fork_init (ev_fork *, callback)
+
+Initialises and configures the fork watcher - it has no parameters of any
+kind. There is a C<ev_fork_set> macro, but using it is utterly pointless,
+really.
+
+=back
+
+
+=head2 C<ev_cleanup> - even the best things end
+
+Cleanup watchers are called just before the event loop is being destroyed
+by a call to C<ev_loop_destroy>.
+
+While there is no guarantee that the event loop gets destroyed, cleanup
+watchers provide a convenient method to install cleanup hooks for your
+program, worker threads and so on - you just to make sure to destroy the
+loop when you want them to be invoked.
+
+Cleanup watchers are invoked in the same way as any other watcher. Unlike
+all other watchers, they do not keep a reference to the event loop (which
+makes a lot of sense if you think about it). Like all other watchers, you
+can call libev functions in the callback, except C<ev_cleanup_start>.
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_cleanup_init (ev_cleanup *, callback)
+
+Initialises and configures the cleanup watcher - it has no parameters of
+any kind. There is a C<ev_cleanup_set> macro, but using it is utterly
+pointless, I assure you.
+
+=back
+
+Example: Register an atexit handler to destroy the default loop, so any
+cleanup functions are called.
+
+ static void
+ program_exits (void)
+ {
+ ev_loop_destroy (EV_DEFAULT_UC);
+ }
+
+ ...
+ atexit (program_exits);
+
+
+=head2 C<ev_async> - how to wake up an event loop
+
+In general, you cannot use an C<ev_loop> from multiple threads or other
+asynchronous sources such as signal handlers (as opposed to multiple event
+loops - those are of course safe to use in different threads).
+
+Sometimes, however, you need to wake up an event loop you do not control,
+for example because it belongs to another thread. This is what C<ev_async>
+watchers do: as long as the C<ev_async> watcher is active, you can signal
+it by calling C<ev_async_send>, which is thread- and signal safe.
+
+This functionality is very similar to C<ev_signal> watchers, as signals,
+too, are asynchronous in nature, and signals, too, will be compressed
+(i.e. the number of callback invocations may be less than the number of
+C<ev_async_send> calls). In fact, you could use signal watchers as a kind
+of "global async watchers" by using a watcher on an otherwise unused
+signal, and C<ev_feed_signal> to signal this watcher from another thread,
+even without knowing which loop owns the signal.
+
+=head3 Queueing
+
+C<ev_async> does not support queueing of data in any way. The reason
+is that the author does not know of a simple (or any) algorithm for a
+multiple-writer-single-reader queue that works in all cases and doesn't
+need elaborate support such as pthreads or unportable memory access
+semantics.
+
+That means that if you want to queue data, you have to provide your own
+queue. But at least I can tell you how to implement locking around your
+queue:
+
+=over 4
+
+=item queueing from a signal handler context
+
+To implement race-free queueing, you simply add to the queue in the signal
+handler but you block the signal handler in the watcher callback. Here is
+an example that does that for some fictitious SIGUSR1 handler:
+
+ static ev_async mysig;
+
+ static void
+ sigusr1_handler (void)
+ {
+ sometype data;
+
+ // no locking etc.
+ queue_put (data);
+ ev_async_send (EV_DEFAULT_ &mysig);
+ }
+
+ static void
+ mysig_cb (EV_P_ ev_async *w, int revents)
+ {
+ sometype data;
+ sigset_t block, prev;
+
+ sigemptyset (&block);
+ sigaddset (&block, SIGUSR1);
+ sigprocmask (SIG_BLOCK, &block, &prev);
+
+ while (queue_get (&data))
+ process (data);
+
+ if (sigismember (&prev, SIGUSR1)
+ sigprocmask (SIG_UNBLOCK, &block, 0);
+ }
+
+(Note: pthreads in theory requires you to use C<pthread_setmask>
+instead of C<sigprocmask> when you use threads, but libev doesn't do it
+either...).
+
+=item queueing from a thread context
+
+The strategy for threads is different, as you cannot (easily) block
+threads but you can easily preempt them, so to queue safely you need to
+employ a traditional mutex lock, such as in this pthread example:
+
+ static ev_async mysig;
+ static pthread_mutex_t mymutex = PTHREAD_MUTEX_INITIALIZER;
+
+ static void
+ otherthread (void)
+ {
+ // only need to lock the actual queueing operation
+ pthread_mutex_lock (&mymutex);
+ queue_put (data);
+ pthread_mutex_unlock (&mymutex);
+
+ ev_async_send (EV_DEFAULT_ &mysig);
+ }
+
+ static void
+ mysig_cb (EV_P_ ev_async *w, int revents)
+ {
+ pthread_mutex_lock (&mymutex);
+
+ while (queue_get (&data))
+ process (data);
+
+ pthread_mutex_unlock (&mymutex);
+ }
+
+=back
+
+
+=head3 Watcher-Specific Functions and Data Members
+
+=over 4
+
+=item ev_async_init (ev_async *, callback)
+
+Initialises and configures the async watcher - it has no parameters of any
+kind. There is a C<ev_async_set> macro, but using it is utterly pointless,
+trust me.
+
+=item ev_async_send (loop, ev_async *)
+
+Sends/signals/activates the given C<ev_async> watcher, that is, feeds
+an C<EV_ASYNC> event on the watcher into the event loop, and instantly
+returns.
+
+Unlike C<ev_feed_event>, this call is safe to do from other threads,
+signal or similar contexts (see the discussion of C<EV_ATOMIC_T> in the
+embedding section below on what exactly this means).
+
+Note that, as with other watchers in libev, multiple events might get
+compressed into a single callback invocation (another way to look at
+this is that C<ev_async> watchers are level-triggered: they are set on
+C<ev_async_send>, reset when the event loop detects that).
+
+This call incurs the overhead of at most one extra system call per event
+loop iteration, if the event loop is blocked, and no syscall at all if
+the event loop (or your program) is processing events. That means that
+repeated calls are basically free (there is no need to avoid calls for
+performance reasons) and that the overhead becomes smaller (typically
+zero) under load.
+
+=item bool = ev_async_pending (ev_async *)
+
+Returns a non-zero value when C<ev_async_send> has been called on the
+watcher but the event has not yet been processed (or even noted) by the
+event loop.
+
+C<ev_async_send> sets a flag in the watcher and wakes up the loop. When
+the loop iterates next and checks for the watcher to have become active,
+it will reset the flag again. C<ev_async_pending> can be used to very
+quickly check whether invoking the loop might be a good idea.
+
+Not that this does I<not> check whether the watcher itself is pending,
+only whether it has been requested to make this watcher pending: there
+is a time window between the event loop checking and resetting the async
+notification, and the callback being invoked.
+
+=back
+
+
+=head1 OTHER FUNCTIONS
+
+There are some other functions of possible interest. Described. Here. Now.
+
+=over 4
+
+=item ev_once (loop, int fd, int events, ev_tstamp timeout, callback)
+
+This function combines a simple timer and an I/O watcher, calls your
+callback on whichever event happens first and automatically stops both
+watchers. This is useful if you want to wait for a single event on an fd
+or timeout without having to allocate/configure/start/stop/free one or
+more watchers yourself.
+
+If C<fd> is less than 0, then no I/O watcher will be started and the
+C<events> argument is being ignored. Otherwise, an C<ev_io> watcher for
+the given C<fd> and C<events> set will be created and started.
+
+If C<timeout> is less than 0, then no timeout watcher will be
+started. Otherwise an C<ev_timer> watcher with after = C<timeout> (and
+repeat = 0) will be started. C<0> is a valid timeout.
+
+The callback has the type C<void (*cb)(int revents, void *arg)> and is
+passed an C<revents> set like normal event callbacks (a combination of
+C<EV_ERROR>, C<EV_READ>, C<EV_WRITE> or C<EV_TIMER>) and the C<arg>
+value passed to C<ev_once>. Note that it is possible to receive I<both>
+a timeout and an io event at the same time - you probably should give io
+events precedence.
+
+Example: wait up to ten seconds for data to appear on STDIN_FILENO.
+
+ static void stdin_ready (int revents, void *arg)
+ {
+ if (revents & EV_READ)
+ /* stdin might have data for us, joy! */;
+ else if (revents & EV_TIMER)
+ /* doh, nothing entered */;
+ }
+
+ ev_once (STDIN_FILENO, EV_READ, 10., stdin_ready, 0);
+
+=item ev_feed_fd_event (loop, int fd, int revents)
+
+Feed an event on the given fd, as if a file descriptor backend detected
+the given events.
+
+=item ev_feed_signal_event (loop, int signum)
+
+Feed an event as if the given signal occurred. See also C<ev_feed_signal>,
+which is async-safe.
+
+=back
+
+
+=head1 COMMON OR USEFUL IDIOMS (OR BOTH)
+
+This section explains some common idioms that are not immediately
+obvious. Note that examples are sprinkled over the whole manual, and this
+section only contains stuff that wouldn't fit anywhere else.
+
+=head2 ASSOCIATING CUSTOM DATA WITH A WATCHER
+
+Each watcher has, by default, a C<void *data> member that you can read
+or modify at any time: libev will completely ignore it. This can be used
+to associate arbitrary data with your watcher. If you need more data and
+don't want to allocate memory separately and store a pointer to it in that
+data member, you can also "subclass" the watcher type and provide your own
+data:
+
+ struct my_io
+ {
+ ev_io io;
+ int otherfd;
+ void *somedata;
+ struct whatever *mostinteresting;
+ };
+
+ ...
+ struct my_io w;
+ ev_io_init (&w.io, my_cb, fd, EV_READ);
+
+And since your callback will be called with a pointer to the watcher, you
+can cast it back to your own type:
+
+ static void my_cb (struct ev_loop *loop, ev_io *w_, int revents)
+ {
+ struct my_io *w = (struct my_io *)w_;
+ ...
+ }
+
+More interesting and less C-conformant ways of casting your callback
+function type instead have been omitted.
+
+=head2 BUILDING YOUR OWN COMPOSITE WATCHERS
+
+Another common scenario is to use some data structure with multiple
+embedded watchers, in effect creating your own watcher that combines
+multiple libev event sources into one "super-watcher":
+
+ struct my_biggy
+ {
+ int some_data;
+ ev_timer t1;
+ ev_timer t2;
+ }
+
+In this case getting the pointer to C<my_biggy> is a bit more
+complicated: Either you store the address of your C<my_biggy> struct in
+the C<data> member of the watcher (for woozies or C++ coders), or you need
+to use some pointer arithmetic using C<offsetof> inside your watchers (for
+real programmers):
+
+ #include <stddef.h>
+
+ static void
+ t1_cb (EV_P_ ev_timer *w, int revents)
+ {
+ struct my_biggy big = (struct my_biggy *)
+ (((char *)w) - offsetof (struct my_biggy, t1));
+ }
+
+ static void
+ t2_cb (EV_P_ ev_timer *w, int revents)
+ {
+ struct my_biggy big = (struct my_biggy *)
+ (((char *)w) - offsetof (struct my_biggy, t2));
+ }
+
+=head2 AVOIDING FINISHING BEFORE RETURNING
+
+Often you have structures like this in event-based programs:
+
+ callback ()
+ {
+ free (request);
+ }
+
+ request = start_new_request (..., callback);
+
+The intent is to start some "lengthy" operation. The C<request> could be
+used to cancel the operation, or do other things with it.
+
+It's not uncommon to have code paths in C<start_new_request> that
+immediately invoke the callback, for example, to report errors. Or you add
+some caching layer that finds that it can skip the lengthy aspects of the
+operation and simply invoke the callback with the result.
+
+The problem here is that this will happen I<before> C<start_new_request>
+has returned, so C<request> is not set.
+
+Even if you pass the request by some safer means to the callback, you
+might want to do something to the request after starting it, such as
+canceling it, which probably isn't working so well when the callback has
+already been invoked.
+
+A common way around all these issues is to make sure that
+C<start_new_request> I<always> returns before the callback is invoked. If
+C<start_new_request> immediately knows the result, it can artificially
+delay invoking the callback by using a C<prepare> or C<idle> watcher for
+example, or more sneakily, by reusing an existing (stopped) watcher and
+pushing it into the pending queue:
+
+ ev_set_cb (watcher, callback);
+ ev_feed_event (EV_A_ watcher, 0);
+
+This way, C<start_new_request> can safely return before the callback is
+invoked, while not delaying callback invocation too much.
+
+=head2 MODEL/NESTED EVENT LOOP INVOCATIONS AND EXIT CONDITIONS
+
+Often (especially in GUI toolkits) there are places where you have
+I<modal> interaction, which is most easily implemented by recursively
+invoking C<ev_run>.
+
+This brings the problem of exiting - a callback might want to finish the
+main C<ev_run> call, but not the nested one (e.g. user clicked "Quit", but
+a modal "Are you sure?" dialog is still waiting), or just the nested one
+and not the main one (e.g. user clocked "Ok" in a modal dialog), or some
+other combination: In these cases, a simple C<ev_break> will not work.
+
+The solution is to maintain "break this loop" variable for each C<ev_run>
+invocation, and use a loop around C<ev_run> until the condition is
+triggered, using C<EVRUN_ONCE>:
+
+ // main loop
+ int exit_main_loop = 0;
+
+ while (!exit_main_loop)
+ ev_run (EV_DEFAULT_ EVRUN_ONCE);
+
+ // in a modal watcher
+ int exit_nested_loop = 0;
+
+ while (!exit_nested_loop)
+ ev_run (EV_A_ EVRUN_ONCE);
+
+To exit from any of these loops, just set the corresponding exit variable:
+
+ // exit modal loop
+ exit_nested_loop = 1;
+
+ // exit main program, after modal loop is finished
+ exit_main_loop = 1;
+
+ // exit both
+ exit_main_loop = exit_nested_loop = 1;
+
+=head2 THREAD LOCKING EXAMPLE
+
+Here is a fictitious example of how to run an event loop in a different
+thread from where callbacks are being invoked and watchers are
+created/added/removed.
+
+For a real-world example, see the C<EV::Loop::Async> perl module,
+which uses exactly this technique (which is suited for many high-level
+languages).
+
+The example uses a pthread mutex to protect the loop data, a condition
+variable to wait for callback invocations, an async watcher to notify the
+event loop thread and an unspecified mechanism to wake up the main thread.
+
+First, you need to associate some data with the event loop:
+
+ typedef struct {
+ mutex_t lock; /* global loop lock */
+ ev_async async_w;
+ thread_t tid;
+ cond_t invoke_cv;
+ } userdata;
+
+ void prepare_loop (EV_P)
+ {
+ // for simplicity, we use a static userdata struct.
+ static userdata u;
+
+ ev_async_init (&u->async_w, async_cb);
+ ev_async_start (EV_A_ &u->async_w);
+
+ pthread_mutex_init (&u->lock, 0);
+ pthread_cond_init (&u->invoke_cv, 0);
+
+ // now associate this with the loop
+ ev_set_userdata (EV_A_ u);
+ ev_set_invoke_pending_cb (EV_A_ l_invoke);
+ ev_set_loop_release_cb (EV_A_ l_release, l_acquire);
+
+ // then create the thread running ev_run
+ pthread_create (&u->tid, 0, l_run, EV_A);
+ }
+
+The callback for the C<ev_async> watcher does nothing: the watcher is used
+solely to wake up the event loop so it takes notice of any new watchers
+that might have been added:
+
+ static void
+ async_cb (EV_P_ ev_async *w, int revents)
+ {
+ // just used for the side effects
+ }
+
+The C<l_release> and C<l_acquire> callbacks simply unlock/lock the mutex
+protecting the loop data, respectively.
+
+ static void
+ l_release (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+ pthread_mutex_unlock (&u->lock);
+ }
+
+ static void
+ l_acquire (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+ pthread_mutex_lock (&u->lock);
+ }
+
+The event loop thread first acquires the mutex, and then jumps straight
+into C<ev_run>:
+
+ void *
+ l_run (void *thr_arg)
+ {
+ struct ev_loop *loop = (struct ev_loop *)thr_arg;
+
+ l_acquire (EV_A);
+ pthread_setcanceltype (PTHREAD_CANCEL_ASYNCHRONOUS, 0);
+ ev_run (EV_A_ 0);
+ l_release (EV_A);
+
+ return 0;
+ }
+
+Instead of invoking all pending watchers, the C<l_invoke> callback will
+signal the main thread via some unspecified mechanism (signals? pipe
+writes? C<Async::Interrupt>?) and then waits until all pending watchers
+have been called (in a while loop because a) spurious wakeups are possible
+and b) skipping inter-thread-communication when there are no pending
+watchers is very beneficial):
+
+ static void
+ l_invoke (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+
+ while (ev_pending_count (EV_A))
+ {
+ wake_up_other_thread_in_some_magic_or_not_so_magic_way ();
+ pthread_cond_wait (&u->invoke_cv, &u->lock);
+ }
+ }
+
+Now, whenever the main thread gets told to invoke pending watchers, it
+will grab the lock, call C<ev_invoke_pending> and then signal the loop
+thread to continue:
+
+ static void
+ real_invoke_pending (EV_P)
+ {
+ userdata *u = ev_userdata (EV_A);
+
+ pthread_mutex_lock (&u->lock);
+ ev_invoke_pending (EV_A);
+ pthread_cond_signal (&u->invoke_cv);
+ pthread_mutex_unlock (&u->lock);
+ }
+
+Whenever you want to start/stop a watcher or do other modifications to an
+event loop, you will now have to lock:
+
+ ev_timer timeout_watcher;
+ userdata *u = ev_userdata (EV_A);
+
+ ev_timer_init (&timeout_watcher, timeout_cb, 5.5, 0.);
+
+ pthread_mutex_lock (&u->lock);
+ ev_timer_start (EV_A_ &timeout_watcher);
+ ev_async_send (EV_A_ &u->async_w);
+ pthread_mutex_unlock (&u->lock);
+
+Note that sending the C<ev_async> watcher is required because otherwise
+an event loop currently blocking in the kernel will have no knowledge
+about the newly added timer. By waking up the loop it will pick up any new
+watchers in the next event loop iteration.
+
+=head2 THREADS, COROUTINES, CONTINUATIONS, QUEUES... INSTEAD OF CALLBACKS
+
+While the overhead of a callback that e.g. schedules a thread is small, it
+is still an overhead. If you embed libev, and your main usage is with some
+kind of threads or coroutines, you might want to customise libev so that
+doesn't need callbacks anymore.
+
+Imagine you have coroutines that you can switch to using a function
+C<switch_to (coro)>, that libev runs in a coroutine called C<libev_coro>
+and that due to some magic, the currently active coroutine is stored in a
+global called C<current_coro>. Then you can build your own "wait for libev
+event" primitive by changing C<EV_CB_DECLARE> and C<EV_CB_INVOKE> (note
+the differing C<;> conventions):
+
+ #define EV_CB_DECLARE(type) struct my_coro *cb;
+ #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb)
+
+That means instead of having a C callback function, you store the
+coroutine to switch to in each watcher, and instead of having libev call
+your callback, you instead have it switch to that coroutine.
+
+A coroutine might now wait for an event with a function called
+C<wait_for_event>. (the watcher needs to be started, as always, but it doesn't
+matter when, or whether the watcher is active or not when this function is
+called):
+
+ void
+ wait_for_event (ev_watcher *w)
+ {
+ ev_set_cb (w, current_coro);
+ switch_to (libev_coro);
+ }
+
+That basically suspends the coroutine inside C<wait_for_event> and
+continues the libev coroutine, which, when appropriate, switches back to
+this or any other coroutine.
+
+You can do similar tricks if you have, say, threads with an event queue -
+instead of storing a coroutine, you store the queue object and instead of
+switching to a coroutine, you push the watcher onto the queue and notify
+any waiters.
+
+To embed libev, see L</EMBEDDING>, but in short, it's easiest to create two
+files, F<my_ev.h> and F<my_ev.c> that include the respective libev files:
+
+ // my_ev.h
+ #define EV_CB_DECLARE(type) struct my_coro *cb;
+ #define EV_CB_INVOKE(watcher) switch_to ((watcher)->cb)
+ #include "../libev/ev.h"
+
+ // my_ev.c
+ #define EV_H "my_ev.h"
+ #include "../libev/ev.c"
+
+And then use F<my_ev.h> when you would normally use F<ev.h>, and compile
+F<my_ev.c> into your project. When properly specifying include paths, you
+can even use F<ev.h> as header file name directly.
+
+
+=head1 LIBEVENT EMULATION
+
+Libev offers a compatibility emulation layer for libevent. It cannot
+emulate the internals of libevent, so here are some usage hints:
+
+=over 4
+
+=item * Only the libevent-1.4.1-beta API is being emulated.
+
+This was the newest libevent version available when libev was implemented,
+and is still mostly unchanged in 2010.
+
+=item * Use it by including <event.h>, as usual.
+
+=item * The following members are fully supported: ev_base, ev_callback,
+ev_arg, ev_fd, ev_res, ev_events.
+
+=item * Avoid using ev_flags and the EVLIST_*-macros, while it is
+maintained by libev, it does not work exactly the same way as in libevent (consider
+it a private API).
+
+=item * Priorities are not currently supported. Initialising priorities
+will fail and all watchers will have the same priority, even though there
+is an ev_pri field.
+
+=item * In libevent, the last base created gets the signals, in libev, the
+base that registered the signal gets the signals.
+
+=item * Other members are not supported.
+
+=item * The libev emulation is I<not> ABI compatible to libevent, you need
+to use the libev header file and library.
+
+=back
+
+=head1 C++ SUPPORT
+
+=head2 C API
+
+The normal C API should work fine when used from C++: both ev.h and the
+libev sources can be compiled as C++. Therefore, code that uses the C API
+will work fine.
+
+Proper exception specifications might have to be added to callbacks passed
+to libev: exceptions may be thrown only from watcher callbacks, all
+other callbacks (allocator, syserr, loop acquire/release and periodic
+reschedule callbacks) must not throw exceptions, and might need a C<throw
+()> specification. If you have code that needs to be compiled as both C
+and C++ you can use the C<EV_THROW> macro for this:
+
+ static void
+ fatal_error (const char *msg) EV_THROW
+ {
+ perror (msg);
+ abort ();
+ }
+
+ ...
+ ev_set_syserr_cb (fatal_error);
+
+The only API functions that can currently throw exceptions are C<ev_run>,
+C<ev_invoke>, C<ev_invoke_pending> and C<ev_loop_destroy> (the latter
+because it runs cleanup watchers).
+
+Throwing exceptions in watcher callbacks is only supported if libev itself
+is compiled with a C++ compiler or your C and C++ environments allow
+throwing exceptions through C libraries (most do).
+
+=head2 C++ API
+
+Libev comes with some simplistic wrapper classes for C++ that mainly allow
+you to use some convenience methods to start/stop watchers and also change
+the callback model to a model using method callbacks on objects.
+
+To use it,
+
+ #include <ev++.h>
+
+This automatically includes F<ev.h> and puts all of its definitions (many
+of them macros) into the global namespace. All C++ specific things are
+put into the C<ev> namespace. It should support all the same embedding
+options as F<ev.h>, most notably C<EV_MULTIPLICITY>.
+
+Care has been taken to keep the overhead low. The only data member the C++
+classes add (compared to plain C-style watchers) is the event loop pointer
+that the watcher is associated with (or no additional members at all if
+you disable C<EV_MULTIPLICITY> when embedding libev).
+
+Currently, functions, static and non-static member functions and classes
+with C<operator ()> can be used as callbacks. Other types should be easy
+to add as long as they only need one additional pointer for context. If
+you need support for other types of functors please contact the author
+(preferably after implementing it).
+
+For all this to work, your C++ compiler either has to use the same calling
+conventions as your C compiler (for static member functions), or you have
+to embed libev and compile libev itself as C++.
+
+Here is a list of things available in the C<ev> namespace:
+
+=over 4
+
+=item C<ev::READ>, C<ev::WRITE> etc.
+
+These are just enum values with the same values as the C<EV_READ> etc.
+macros from F<ev.h>.
+
+=item C<ev::tstamp>, C<ev::now>
+
+Aliases to the same types/functions as with the C<ev_> prefix.
+
+=item C<ev::io>, C<ev::timer>, C<ev::periodic>, C<ev::idle>, C<ev::sig> etc.
+
+For each C<ev_TYPE> watcher in F<ev.h> there is a corresponding class of
+the same name in the C<ev> namespace, with the exception of C<ev_signal>
+which is called C<ev::sig> to avoid clashes with the C<signal> macro
+defined by many implementations.
+
+All of those classes have these methods:
+
+=over 4
+
+=item ev::TYPE::TYPE ()
+
+=item ev::TYPE::TYPE (loop)
+
+=item ev::TYPE::~TYPE
+
+The constructor (optionally) takes an event loop to associate the watcher
+with. If it is omitted, it will use C<EV_DEFAULT>.
+
+The constructor calls C<ev_init> for you, which means you have to call the
+C<set> method before starting it.
+
+It will not set a callback, however: You have to call the templated C<set>
+method to set a callback before you can start the watcher.
+
+(The reason why you have to use a method is a limitation in C++ which does
+not allow explicit template arguments for constructors).
+
+The destructor automatically stops the watcher if it is active.
+
+=item w->set<class, &class::method> (object *)
+
+This method sets the callback method to call. The method has to have a
+signature of C<void (*)(ev_TYPE &, int)>, it receives the watcher as
+first argument and the C<revents> as second. The object must be given as
+parameter and is stored in the C<data> member of the watcher.
+
+This method synthesizes efficient thunking code to call your method from
+the C callback that libev requires. If your compiler can inline your
+callback (i.e. it is visible to it at the place of the C<set> call and
+your compiler is good :), then the method will be fully inlined into the
+thunking function, making it as fast as a direct C callback.
+
+Example: simple class declaration and watcher initialisation
+
+ struct myclass
+ {
+ void io_cb (ev::io &w, int revents) { }
+ }
+
+ myclass obj;
+ ev::io iow;
+ iow.set <myclass, &myclass::io_cb> (&obj);
+
+=item w->set (object *)
+
+This is a variation of a method callback - leaving out the method to call
+will default the method to C<operator ()>, which makes it possible to use
+functor objects without having to manually specify the C<operator ()> all
+the time. Incidentally, you can then also leave out the template argument
+list.
+
+The C<operator ()> method prototype must be C<void operator ()(watcher &w,
+int revents)>.
+
+See the method-C<set> above for more details.
+
+Example: use a functor object as callback.
+
+ struct myfunctor
+ {
+ void operator() (ev::io &w, int revents)
+ {
+ ...
+ }
+ }
+
+ myfunctor f;
+
+ ev::io w;
+ w.set (&f);
+
+=item w->set<function> (void *data = 0)
+
+Also sets a callback, but uses a static method or plain function as
+callback. The optional C<data> argument will be stored in the watcher's
+C<data> member and is free for you to use.
+
+The prototype of the C<function> must be C<void (*)(ev::TYPE &w, int)>.
+
+See the method-C<set> above for more details.
+
+Example: Use a plain function as callback.
+
+ static void io_cb (ev::io &w, int revents) { }
+ iow.set <io_cb> ();
+
+=item w->set (loop)
+
+Associates a different C<struct ev_loop> with this watcher. You can only
+do this when the watcher is inactive (and not pending either).
+
+=item w->set ([arguments])
+
+Basically the same as C<ev_TYPE_set> (except for C<ev::embed> watchers>),
+with the same arguments. Either this method or a suitable start method
+must be called at least once. Unlike the C counterpart, an active watcher
+gets automatically stopped and restarted when reconfiguring it with this
+method.
+
+For C<ev::embed> watchers this method is called C<set_embed>, to avoid
+clashing with the C<set (loop)> method.
+
+=item w->start ()
+
+Starts the watcher. Note that there is no C<loop> argument, as the
+constructor already stores the event loop.
+
+=item w->start ([arguments])
+
+Instead of calling C<set> and C<start> methods separately, it is often
+convenient to wrap them in one call. Uses the same type of arguments as
+the configure C<set> method of the watcher.
+
+=item w->stop ()
+
+Stops the watcher if it is active. Again, no C<loop> argument.
+
+=item w->again () (C<ev::timer>, C<ev::periodic> only)
+
+For C<ev::timer> and C<ev::periodic>, this invokes the corresponding
+C<ev_TYPE_again> function.
+
+=item w->sweep () (C<ev::embed> only)
+
+Invokes C<ev_embed_sweep>.
+
+=item w->update () (C<ev::stat> only)
+
+Invokes C<ev_stat_stat>.
+
+=back
+
+=back
+
+Example: Define a class with two I/O and idle watchers, start the I/O
+watchers in the constructor.
+
+ class myclass
+ {
+ ev::io io ; void io_cb (ev::io &w, int revents);
+ ev::io io2 ; void io2_cb (ev::io &w, int revents);
+ ev::idle idle; void idle_cb (ev::idle &w, int revents);
+
+ myclass (int fd)
+ {
+ io .set <myclass, &myclass::io_cb > (this);
+ io2 .set <myclass, &myclass::io2_cb > (this);
+ idle.set <myclass, &myclass::idle_cb> (this);
+
+ io.set (fd, ev::WRITE); // configure the watcher
+ io.start (); // start it whenever convenient
+
+ io2.start (fd, ev::READ); // set + start in one call
+ }
+ };
+
+
+=head1 OTHER LANGUAGE BINDINGS
+
+Libev does not offer other language bindings itself, but bindings for a
+number of languages exist in the form of third-party packages. If you know
+any interesting language binding in addition to the ones listed here, drop
+me a note.
+
+=over 4
+
+=item Perl
+
+The EV module implements the full libev API and is actually used to test
+libev. EV is developed together with libev. Apart from the EV core module,
+there are additional modules that implement libev-compatible interfaces
+to C<libadns> (C<EV::ADNS>, but C<AnyEvent::DNS> is preferred nowadays),
+C<Net::SNMP> (C<Net::SNMP::EV>) and the C<libglib> event core (C<Glib::EV>
+and C<EV::Glib>).
+
+It can be found and installed via CPAN, its homepage is at
+L<http://software.schmorp.de/pkg/EV>.
+
+=item Python
+
+Python bindings can be found at L<http://code.google.com/p/pyev/>. It
+seems to be quite complete and well-documented.
+
+=item Ruby
+
+Tony Arcieri has written a ruby extension that offers access to a subset
+of the libev API and adds file handle abstractions, asynchronous DNS and
+more on top of it. It can be found via gem servers. Its homepage is at
+L<http://rev.rubyforge.org/>.
+
+Roger Pack reports that using the link order C<-lws2_32 -lmsvcrt-ruby-190>
+makes rev work even on mingw.
+
+=item Haskell
+
+A haskell binding to libev is available at
+L<http://hackage.haskell.org/cgi-bin/hackage-scripts/package/hlibev>.
+
+=item D
+
+Leandro Lucarella has written a D language binding (F<ev.d>) for libev, to
+be found at L<http://www.llucax.com.ar/proj/ev.d/index.html>.
+
+=item Ocaml
+
+Erkki Seppala has written Ocaml bindings for libev, to be found at
+L<http://modeemi.cs.tut.fi/~flux/software/ocaml-ev/>.
+
+=item Lua
+
+Brian Maher has written a partial interface to libev for lua (at the
+time of this writing, only C<ev_io> and C<ev_timer>), to be found at
+L<http://github.com/brimworks/lua-ev>.
+
+=item Javascript
+
+Node.js (L<http://nodejs.org>) uses libev as the underlying event library.
+
+=item Others
+
+There are others, and I stopped counting.
+
+=back
+
+
+=head1 MACRO MAGIC
+
+Libev can be compiled with a variety of options, the most fundamental
+of which is C<EV_MULTIPLICITY>. This option determines whether (most)
+functions and callbacks have an initial C<struct ev_loop *> argument.
+
+To make it easier to write programs that cope with either variant, the
+following macros are defined:
+
+=over 4
+
+=item C<EV_A>, C<EV_A_>
+
+This provides the loop I<argument> for functions, if one is required ("ev
+loop argument"). The C<EV_A> form is used when this is the sole argument,
+C<EV_A_> is used when other arguments are following. Example:
+
+ ev_unref (EV_A);
+ ev_timer_add (EV_A_ watcher);
+ ev_run (EV_A_ 0);
+
+It assumes the variable C<loop> of type C<struct ev_loop *> is in scope,
+which is often provided by the following macro.
+
+=item C<EV_P>, C<EV_P_>
+
+This provides the loop I<parameter> for functions, if one is required ("ev
+loop parameter"). The C<EV_P> form is used when this is the sole parameter,
+C<EV_P_> is used when other parameters are following. Example:
+
+ // this is how ev_unref is being declared
+ static void ev_unref (EV_P);
+
+ // this is how you can declare your typical callback
+ static void cb (EV_P_ ev_timer *w, int revents)
+
+It declares a parameter C<loop> of type C<struct ev_loop *>, quite
+suitable for use with C<EV_A>.
+
+=item C<EV_DEFAULT>, C<EV_DEFAULT_>
+
+Similar to the other two macros, this gives you the value of the default
+loop, if multiple loops are supported ("ev loop default"). The default loop
+will be initialised if it isn't already initialised.
+
+For non-multiplicity builds, these macros do nothing, so you always have
+to initialise the loop somewhere.
+
+=item C<EV_DEFAULT_UC>, C<EV_DEFAULT_UC_>
+
+Usage identical to C<EV_DEFAULT> and C<EV_DEFAULT_>, but requires that the
+default loop has been initialised (C<UC> == unchecked). Their behaviour
+is undefined when the default loop has not been initialised by a previous
+execution of C<EV_DEFAULT>, C<EV_DEFAULT_> or C<ev_default_init (...)>.
+
+It is often prudent to use C<EV_DEFAULT> when initialising the first
+watcher in a function but use C<EV_DEFAULT_UC> afterwards.
+
+=back
+
+Example: Declare and initialise a check watcher, utilising the above
+macros so it will work regardless of whether multiple loops are supported
+or not.
+
+ static void
+ check_cb (EV_P_ ev_timer *w, int revents)
+ {
+ ev_check_stop (EV_A_ w);
+ }
+
+ ev_check check;
+ ev_check_init (&check, check_cb);
+ ev_check_start (EV_DEFAULT_ &check);
+ ev_run (EV_DEFAULT_ 0);
+
+=head1 EMBEDDING
+
+Libev can (and often is) directly embedded into host
+applications. Examples of applications that embed it include the Deliantra
+Game Server, the EV perl module, the GNU Virtual Private Ethernet (gvpe)
+and rxvt-unicode.
+
+The goal is to enable you to just copy the necessary files into your
+source directory without having to change even a single line in them, so
+you can easily upgrade by simply copying (or having a checked-out copy of
+libev somewhere in your source tree).
+
+=head2 FILESETS
+
+Depending on what features you need you need to include one or more sets of files
+in your application.
+
+=head3 CORE EVENT LOOP
+
+To include only the libev core (all the C<ev_*> functions), with manual
+configuration (no autoconf):
+
+ #define EV_STANDALONE 1
+ #include "ev.c"
+
+This will automatically include F<ev.h>, too, and should be done in a
+single C source file only to provide the function implementations. To use
+it, do the same for F<ev.h> in all files wishing to use this API (best
+done by writing a wrapper around F<ev.h> that you can include instead and
+where you can put other configuration options):
+
+ #define EV_STANDALONE 1
+ #include "ev.h"
+
+Both header files and implementation files can be compiled with a C++
+compiler (at least, that's a stated goal, and breakage will be treated
+as a bug).
+
+You need the following files in your source tree, or in a directory
+in your include path (e.g. in libev/ when using -Ilibev):
+
+ ev.h
+ ev.c
+ ev_vars.h
+ ev_wrap.h
+
+ ev_win32.c required on win32 platforms only
+
+ ev_select.c only when select backend is enabled
+ ev_poll.c only when poll backend is enabled
+ ev_epoll.c only when the epoll backend is enabled
+ ev_kqueue.c only when the kqueue backend is enabled
+ ev_port.c only when the solaris port backend is enabled
+
+F<ev.c> includes the backend files directly when enabled, so you only need
+to compile this single file.
+
+=head3 LIBEVENT COMPATIBILITY API
+
+To include the libevent compatibility API, also include:
+
+ #include "event.c"
+
+in the file including F<ev.c>, and:
+
+ #include "event.h"
+
+in the files that want to use the libevent API. This also includes F<ev.h>.
+
+You need the following additional files for this:
+
+ event.h
+ event.c
+
+=head3 AUTOCONF SUPPORT
+
+Instead of using C<EV_STANDALONE=1> and providing your configuration in
+whatever way you want, you can also C<m4_include([libev.m4])> in your
+F<configure.ac> and leave C<EV_STANDALONE> undefined. F<ev.c> will then
+include F<config.h> and configure itself accordingly.
+
+For this of course you need the m4 file:
+
+ libev.m4
+
+=head2 PREPROCESSOR SYMBOLS/MACROS
+
+Libev can be configured via a variety of preprocessor symbols you have to
+define before including (or compiling) any of its files. The default in
+the absence of autoconf is documented for every option.
+
+Symbols marked with "(h)" do not change the ABI, and can have different
+values when compiling libev vs. including F<ev.h>, so it is permissible
+to redefine them before including F<ev.h> without breaking compatibility
+to a compiled library. All other symbols change the ABI, which means all
+users of libev and the libev code itself must be compiled with compatible
+settings.
+
+=over 4
+
+=item EV_COMPAT3 (h)
+
+Backwards compatibility is a major concern for libev. This is why this
+release of libev comes with wrappers for the functions and symbols that
+have been renamed between libev version 3 and 4.
+
+You can disable these wrappers (to test compatibility with future
+versions) by defining C<EV_COMPAT3> to C<0> when compiling your
+sources. This has the additional advantage that you can drop the C<struct>
+from C<struct ev_loop> declarations, as libev will provide an C<ev_loop>
+typedef in that case.
+
+In some future version, the default for C<EV_COMPAT3> will become C<0>,
+and in some even more future version the compatibility code will be
+removed completely.
+
+=item EV_STANDALONE (h)
+
+Must always be C<1> if you do not use autoconf configuration, which
+keeps libev from including F<config.h>, and it also defines dummy
+implementations for some libevent functions (such as logging, which is not
+supported). It will also not define any of the structs usually found in
+F<event.h> that are not directly supported by the libev core alone.
+
+In standalone mode, libev will still try to automatically deduce the
+configuration, but has to be more conservative.
+
+=item EV_USE_FLOOR
+
+If defined to be C<1>, libev will use the C<floor ()> function for its
+periodic reschedule calculations, otherwise libev will fall back on a
+portable (slower) implementation. If you enable this, you usually have to
+link against libm or something equivalent. Enabling this when the C<floor>
+function is not available will fail, so the safe default is to not enable
+this.
+
+=item EV_USE_MONOTONIC
+
+If defined to be C<1>, libev will try to detect the availability of the
+monotonic clock option at both compile time and runtime. Otherwise no
+use of the monotonic clock option will be attempted. If you enable this,
+you usually have to link against librt or something similar. Enabling it
+when the functionality isn't available is safe, though, although you have
+to make sure you link against any libraries where the C<clock_gettime>
+function is hiding in (often F<-lrt>). See also C<EV_USE_CLOCK_SYSCALL>.
+
+=item EV_USE_REALTIME
+
+If defined to be C<1>, libev will try to detect the availability of the
+real-time clock option at compile time (and assume its availability
+at runtime if successful). Otherwise no use of the real-time clock
+option will be attempted. This effectively replaces C<gettimeofday>
+by C<clock_get (CLOCK_REALTIME, ...)> and will not normally affect
+correctness. See the note about libraries in the description of
+C<EV_USE_MONOTONIC>, though. Defaults to the opposite value of
+C<EV_USE_CLOCK_SYSCALL>.
+
+=item EV_USE_CLOCK_SYSCALL
+
+If defined to be C<1>, libev will try to use a direct syscall instead
+of calling the system-provided C<clock_gettime> function. This option
+exists because on GNU/Linux, C<clock_gettime> is in C<librt>, but C<librt>
+unconditionally pulls in C<libpthread>, slowing down single-threaded
+programs needlessly. Using a direct syscall is slightly slower (in
+theory), because no optimised vdso implementation can be used, but avoids
+the pthread dependency. Defaults to C<1> on GNU/Linux with glibc 2.x or
+higher, as it simplifies linking (no need for C<-lrt>).
+
+=item EV_USE_NANOSLEEP
+
+If defined to be C<1>, libev will assume that C<nanosleep ()> is available
+and will use it for delays. Otherwise it will use C<select ()>.
+
+=item EV_USE_EVENTFD
+
+If defined to be C<1>, then libev will assume that C<eventfd ()> is
+available and will probe for kernel support at runtime. This will improve
+C<ev_signal> and C<ev_async> performance and reduce resource consumption.
+If undefined, it will be enabled if the headers indicate GNU/Linux + Glibc
+2.7 or newer, otherwise disabled.
+
+=item EV_USE_SELECT
+
+If undefined or defined to be C<1>, libev will compile in support for the
+C<select>(2) backend. No attempt at auto-detection will be done: if no
+other method takes over, select will be it. Otherwise the select backend
+will not be compiled in.
+
+=item EV_SELECT_USE_FD_SET
+
+If defined to C<1>, then the select backend will use the system C<fd_set>
+structure. This is useful if libev doesn't compile due to a missing
+C<NFDBITS> or C<fd_mask> definition or it mis-guesses the bitset layout
+on exotic systems. This usually limits the range of file descriptors to
+some low limit such as 1024 or might have other limitations (winsocket
+only allows 64 sockets). The C<FD_SETSIZE> macro, set before compilation,
+configures the maximum size of the C<fd_set>.
+
+=item EV_SELECT_IS_WINSOCKET
+
+When defined to C<1>, the select backend will assume that
+select/socket/connect etc. don't understand file descriptors but
+wants osf handles on win32 (this is the case when the select to
+be used is the winsock select). This means that it will call
+C<_get_osfhandle> on the fd to convert it to an OS handle. Otherwise,
+it is assumed that all these functions actually work on fds, even
+on win32. Should not be defined on non-win32 platforms.
+
+=item EV_FD_TO_WIN32_HANDLE(fd)
+
+If C<EV_SELECT_IS_WINSOCKET> is enabled, then libev needs a way to map
+file descriptors to socket handles. When not defining this symbol (the
+default), then libev will call C<_get_osfhandle>, which is usually
+correct. In some cases, programs use their own file descriptor management,
+in which case they can provide this function to map fds to socket handles.
+
+=item EV_WIN32_HANDLE_TO_FD(handle)
+
+If C<EV_SELECT_IS_WINSOCKET> then libev maps handles to file descriptors
+using the standard C<_open_osfhandle> function. For programs implementing
+their own fd to handle mapping, overwriting this function makes it easier
+to do so. This can be done by defining this macro to an appropriate value.
+
+=item EV_WIN32_CLOSE_FD(fd)
+
+If programs implement their own fd to handle mapping on win32, then this
+macro can be used to override the C<close> function, useful to unregister
+file descriptors again. Note that the replacement function has to close
+the underlying OS handle.
+
+=item EV_USE_WSASOCKET
+
+If defined to be C<1>, libev will use C<WSASocket> to create its internal
+communication socket, which works better in some environments. Otherwise,
+the normal C<socket> function will be used, which works better in other
+environments.
+
+=item EV_USE_POLL
+
+If defined to be C<1>, libev will compile in support for the C<poll>(2)
+backend. Otherwise it will be enabled on non-win32 platforms. It
+takes precedence over select.
+
+=item EV_USE_EPOLL
+
+If defined to be C<1>, libev will compile in support for the Linux
+C<epoll>(7) backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for GNU/Linux systems. If undefined, it will be enabled if the
+headers indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+
+=item EV_USE_KQUEUE
+
+If defined to be C<1>, libev will compile in support for the BSD style
+C<kqueue>(2) backend. Its actual availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for BSD and BSD-like systems, although on most BSDs kqueue only
+supports some types of fds correctly (the only platform we found that
+supports ptys for example was NetBSD), so kqueue might be compiled in, but
+not be used unless explicitly requested. The best way to use it is to find
+out whether kqueue supports your type of fd properly and use an embedded
+kqueue loop.
+
+=item EV_USE_PORT
+
+If defined to be C<1>, libev will compile in support for the Solaris
+10 port style backend. Its availability will be detected at runtime,
+otherwise another method will be used as fallback. This is the preferred
+backend for Solaris 10 systems.
+
+=item EV_USE_DEVPOLL
+
+Reserved for future expansion, works like the USE symbols above.
+
+=item EV_USE_INOTIFY
+
+If defined to be C<1>, libev will compile in support for the Linux inotify
+interface to speed up C<ev_stat> watchers. Its actual availability will
+be detected at runtime. If undefined, it will be enabled if the headers
+indicate GNU/Linux + Glibc 2.4 or newer, otherwise disabled.
+
+=item EV_NO_SMP
+
+If defined to be C<1>, libev will assume that memory is always coherent
+between threads, that is, threads can be used, but threads never run on
+different cpus (or different cpu cores). This reduces dependencies
+and makes libev faster.
+
+=item EV_NO_THREADS
+
+If defined to be C<1>, libev will assume that it will never be called from
+different threads (that includes signal handlers), which is a stronger
+assumption than C<EV_NO_SMP>, above. This reduces dependencies and makes
+libev faster.
+
+=item EV_ATOMIC_T
+
+Libev requires an integer type (suitable for storing C<0> or C<1>) whose
+access is atomic with respect to other threads or signal contexts. No
+such type is easily found in the C language, so you can provide your own
+type that you know is safe for your purposes. It is used both for signal
+handler "locking" as well as for signal and thread safety in C<ev_async>
+watchers.
+
+In the absence of this define, libev will use C<sig_atomic_t volatile>
+(from F<signal.h>), which is usually good enough on most platforms.
+
+=item EV_H (h)
+
+The name of the F<ev.h> header file used to include it. The default if
+undefined is C<"ev.h"> in F<event.h>, F<ev.c> and F<ev++.h>. This can be
+used to virtually rename the F<ev.h> header file in case of conflicts.
+
+=item EV_CONFIG_H (h)
+
+If C<EV_STANDALONE> isn't C<1>, this variable can be used to override
+F<ev.c>'s idea of where to find the F<config.h> file, similarly to
+C<EV_H>, above.
+
+=item EV_EVENT_H (h)
+
+Similarly to C<EV_H>, this macro can be used to override F<event.c>'s idea
+of how the F<event.h> header can be found, the default is C<"event.h">.
+
+=item EV_PROTOTYPES (h)
+
+If defined to be C<0>, then F<ev.h> will not define any function
+prototypes, but still define all the structs and other symbols. This is
+occasionally useful if you want to provide your own wrapper functions
+around libev functions.
+
+=item EV_MULTIPLICITY
+
+If undefined or defined to C<1>, then all event-loop-specific functions
+will have the C<struct ev_loop *> as first argument, and you can create
+additional independent event loops. Otherwise there will be no support
+for multiple event loops and there is no first event loop pointer
+argument. Instead, all functions act on the single default loop.
+
+Note that C<EV_DEFAULT> and C<EV_DEFAULT_> will no longer provide a
+default loop when multiplicity is switched off - you always have to
+initialise the loop manually in this case.
+
+=item EV_MINPRI
+
+=item EV_MAXPRI
+
+The range of allowed priorities. C<EV_MINPRI> must be smaller or equal to
+C<EV_MAXPRI>, but otherwise there are no non-obvious limitations. You can
+provide for more priorities by overriding those symbols (usually defined
+to be C<-2> and C<2>, respectively).
+
+When doing priority-based operations, libev usually has to linearly search
+all the priorities, so having many of them (hundreds) uses a lot of space
+and time, so using the defaults of five priorities (-2 .. +2) is usually
+fine.
+
+If your embedding application does not need any priorities, defining these
+both to C<0> will save some memory and CPU.
+
+=item EV_PERIODIC_ENABLE, EV_IDLE_ENABLE, EV_EMBED_ENABLE, EV_STAT_ENABLE,
+EV_PREPARE_ENABLE, EV_CHECK_ENABLE, EV_FORK_ENABLE, EV_SIGNAL_ENABLE,
+EV_ASYNC_ENABLE, EV_CHILD_ENABLE.
+
+If undefined or defined to be C<1> (and the platform supports it), then
+the respective watcher type is supported. If defined to be C<0>, then it
+is not. Disabling watcher types mainly saves code size.
+
+=item EV_FEATURES
+
+If you need to shave off some kilobytes of code at the expense of some
+speed (but with the full API), you can define this symbol to request
+certain subsets of functionality. The default is to enable all features
+that can be enabled on the platform.
+
+A typical way to use this symbol is to define it to C<0> (or to a bitset
+with some broad features you want) and then selectively re-enable
+additional parts you want, for example if you want everything minimal,
+but multiple event loop support, async and child watchers and the poll
+backend, use this:
+
+ #define EV_FEATURES 0
+ #define EV_MULTIPLICITY 1
+ #define EV_USE_POLL 1
+ #define EV_CHILD_ENABLE 1
+ #define EV_ASYNC_ENABLE 1
+
+The actual value is a bitset, it can be a combination of the following
+values (by default, all of these are enabled):
+
+=over 4
+
+=item C<1> - faster/larger code
+
+Use larger code to speed up some operations.
+
+Currently this is used to override some inlining decisions (enlarging the
+code size by roughly 30% on amd64).
+
+When optimising for size, use of compiler flags such as C<-Os> with
+gcc is recommended, as well as C<-DNDEBUG>, as libev contains a number of
+assertions.
+
+The default is off when C<__OPTIMIZE_SIZE__> is defined by your compiler
+(e.g. gcc with C<-Os>).
+
+=item C<2> - faster/larger data structures
+
+Replaces the small 2-heap for timer management by a faster 4-heap, larger
+hash table sizes and so on. This will usually further increase code size
+and can additionally have an effect on the size of data structures at
+runtime.
+
+The default is off when C<__OPTIMIZE_SIZE__> is defined by your compiler
+(e.g. gcc with C<-Os>).
+
+=item C<4> - full API configuration
+
+This enables priorities (sets C<EV_MAXPRI>=2 and C<EV_MINPRI>=-2), and
+enables multiplicity (C<EV_MULTIPLICITY>=1).
+
+=item C<8> - full API
+
+This enables a lot of the "lesser used" API functions. See C<ev.h> for
+details on which parts of the API are still available without this
+feature, and do not complain if this subset changes over time.
+
+=item C<16> - enable all optional watcher types
+
+Enables all optional watcher types. If you want to selectively enable
+only some watcher types other than I/O and timers (e.g. prepare,
+embed, async, child...) you can enable them manually by defining
+C<EV_watchertype_ENABLE> to C<1> instead.
+
+=item C<32> - enable all backends
+
+This enables all backends - without this feature, you need to enable at
+least one backend manually (C<EV_USE_SELECT> is a good choice).
+
+=item C<64> - enable OS-specific "helper" APIs
+
+Enable inotify, eventfd, signalfd and similar OS-specific helper APIs by
+default.
+
+=back
+
+Compiling with C<gcc -Os -DEV_STANDALONE -DEV_USE_EPOLL=1 -DEV_FEATURES=0>
+reduces the compiled size of libev from 24.7Kb code/2.8Kb data to 6.5Kb
+code/0.3Kb data on my GNU/Linux amd64 system, while still giving you I/O
+watchers, timers and monotonic clock support.
+
+With an intelligent-enough linker (gcc+binutils are intelligent enough
+when you use C<-Wl,--gc-sections -ffunction-sections>) functions unused by
+your program might be left out as well - a binary starting a timer and an
+I/O watcher then might come out at only 5Kb.
+
+=item EV_API_STATIC
+
+If this symbol is defined (by default it is not), then all identifiers
+will have static linkage. This means that libev will not export any
+identifiers, and you cannot link against libev anymore. This can be useful
+when you embed libev, only want to use libev functions in a single file,
+and do not want its identifiers to be visible.
+
+To use this, define C<EV_API_STATIC> and include F<ev.c> in the file that
+wants to use libev.
+
+This option only works when libev is compiled with a C compiler, as C++
+doesn't support the required declaration syntax.
+
+=item EV_AVOID_STDIO
+
+If this is set to C<1> at compiletime, then libev will avoid using stdio
+functions (printf, scanf, perror etc.). This will increase the code size
+somewhat, but if your program doesn't otherwise depend on stdio and your
+libc allows it, this avoids linking in the stdio library which is quite
+big.
+
+Note that error messages might become less precise when this option is
+enabled.
+
+=item EV_NSIG
+
+The highest supported signal number, +1 (or, the number of
+signals): Normally, libev tries to deduce the maximum number of signals
+automatically, but sometimes this fails, in which case it can be
+specified. Also, using a lower number than detected (C<32> should be
+good for about any system in existence) can save some memory, as libev
+statically allocates some 12-24 bytes per signal number.
+
+=item EV_PID_HASHSIZE
+
+C<ev_child> watchers use a small hash table to distribute workload by
+pid. The default size is C<16> (or C<1> with C<EV_FEATURES> disabled),
+usually more than enough. If you need to manage thousands of children you
+might want to increase this value (I<must> be a power of two).
+
+=item EV_INOTIFY_HASHSIZE
+
+C<ev_stat> watchers use a small hash table to distribute workload by
+inotify watch id. The default size is C<16> (or C<1> with C<EV_FEATURES>
+disabled), usually more than enough. If you need to manage thousands of
+C<ev_stat> watchers you might want to increase this value (I<must> be a
+power of two).
+
+=item EV_USE_4HEAP
+
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev uses a 4-heap when this symbol is defined
+to C<1>. The 4-heap uses more complicated (longer) code but has noticeably
+faster performance with many (thousands) of watchers.
+
+The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
+will be C<0>.
+
+=item EV_HEAP_CACHE_AT
+
+Heaps are not very cache-efficient. To improve the cache-efficiency of the
+timer and periodics heaps, libev can cache the timestamp (I<at>) within
+the heap structure (selected by defining C<EV_HEAP_CACHE_AT> to C<1>),
+which uses 8-12 bytes more per watcher and a few hundred bytes more code,
+but avoids random read accesses on heap changes. This improves performance
+noticeably with many (hundreds) of watchers.
+
+The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
+will be C<0>.
+
+=item EV_VERIFY
+
+Controls how much internal verification (see C<ev_verify ()>) will
+be done: If set to C<0>, no internal verification code will be compiled
+in. If set to C<1>, then verification code will be compiled in, but not
+called. If set to C<2>, then the internal verification code will be
+called once per loop, which can slow down libev. If set to C<3>, then the
+verification code will be called very frequently, which will slow down
+libev considerably.
+
+The default is C<1>, unless C<EV_FEATURES> overrides it, in which case it
+will be C<0>.
+
+=item EV_COMMON
+
+By default, all watchers have a C<void *data> member. By redefining
+this macro to something else you can include more and other types of
+members. You have to define it each time you include one of the files,
+though, and it must be identical each time.
+
+For example, the perl EV module uses something like this:
+
+ #define EV_COMMON \
+ SV *self; /* contains this struct */ \
+ SV *cb_sv, *fh /* note no trailing ";" */
+
+=item EV_CB_DECLARE (type)
+
+=item EV_CB_INVOKE (watcher, revents)
+
+=item ev_set_cb (ev, cb)
+
+Can be used to change the callback member declaration in each watcher,
+and the way callbacks are invoked and set. Must expand to a struct member
+definition and a statement, respectively. See the F<ev.h> header file for
+their default definitions. One possible use for overriding these is to
+avoid the C<struct ev_loop *> as first argument in all cases, or to use
+method calls instead of plain function calls in C++.
+
+=back
+
+=head2 EXPORTED API SYMBOLS
+
+If you need to re-export the API (e.g. via a DLL) and you need a list of
+exported symbols, you can use the provided F<Symbol.*> files which list
+all public symbols, one per line:
+
+ Symbols.ev for libev proper
+ Symbols.event for the libevent emulation
+
+This can also be used to rename all public symbols to avoid clashes with
+multiple versions of libev linked together (which is obviously bad in
+itself, but sometimes it is inconvenient to avoid this).
+
+A sed command like this will create wrapper C<#define>'s that you need to
+include before including F<ev.h>:
+
+ <Symbols.ev sed -e "s/.*/#define & myprefix_&/" >wrap.h
+
+This would create a file F<wrap.h> which essentially looks like this:
+
+ #define ev_backend myprefix_ev_backend
+ #define ev_check_start myprefix_ev_check_start
+ #define ev_check_stop myprefix_ev_check_stop
+ ...
+
+=head2 EXAMPLES
+
+For a real-world example of a program the includes libev
+verbatim, you can have a look at the EV perl module
+(L<http://software.schmorp.de/pkg/EV.html>). It has the libev files in
+the F<libev/> subdirectory and includes them in the F<EV/EVAPI.h> (public
+interface) and F<EV.xs> (implementation) files. Only the F<EV.xs> file
+will be compiled. It is pretty complex because it provides its own header
+file.
+
+The usage in rxvt-unicode is simpler. It has a F<ev_cpp.h> header file
+that everybody includes and which overrides some configure choices:
+
+ #define EV_FEATURES 8
+ #define EV_USE_SELECT 1
+ #define EV_PREPARE_ENABLE 1
+ #define EV_IDLE_ENABLE 1
+ #define EV_SIGNAL_ENABLE 1
+ #define EV_CHILD_ENABLE 1
+ #define EV_USE_STDEXCEPT 0
+ #define EV_CONFIG_H <config.h>
+
+ #include "ev++.h"
+
+And a F<ev_cpp.C> implementation file that contains libev proper and is compiled:
+
+ #include "ev_cpp.h"
+ #include "ev.c"
+
+=head1 INTERACTION WITH OTHER PROGRAMS, LIBRARIES OR THE ENVIRONMENT
+
+=head2 THREADS AND COROUTINES
+
+=head3 THREADS
+
+All libev functions are reentrant and thread-safe unless explicitly
+documented otherwise, but libev implements no locking itself. This means
+that you can use as many loops as you want in parallel, as long as there
+are no concurrent calls into any libev function with the same loop
+parameter (C<ev_default_*> calls have an implicit default loop parameter,
+of course): libev guarantees that different event loops share no data
+structures that need any locking.
+
+Or to put it differently: calls with different loop parameters can be done
+concurrently from multiple threads, calls with the same loop parameter
+must be done serially (but can be done from different threads, as long as
+only one thread ever is inside a call at any point in time, e.g. by using
+a mutex per loop).
+
+Specifically to support threads (and signal handlers), libev implements
+so-called C<ev_async> watchers, which allow some limited form of
+concurrency on the same event loop, namely waking it up "from the
+outside".
+
+If you want to know which design (one loop, locking, or multiple loops
+without or something else still) is best for your problem, then I cannot
+help you, but here is some generic advice:
+
+=over 4
+
+=item * most applications have a main thread: use the default libev loop
+in that thread, or create a separate thread running only the default loop.
+
+This helps integrating other libraries or software modules that use libev
+themselves and don't care/know about threading.
+
+=item * one loop per thread is usually a good model.
+
+Doing this is almost never wrong, sometimes a better-performance model
+exists, but it is always a good start.
+
+=item * other models exist, such as the leader/follower pattern, where one
+loop is handed through multiple threads in a kind of round-robin fashion.
+
+Choosing a model is hard - look around, learn, know that usually you can do
+better than you currently do :-)
+
+=item * often you need to talk to some other thread which blocks in the
+event loop.
+
+C<ev_async> watchers can be used to wake them up from other threads safely
+(or from signal contexts...).
+
+An example use would be to communicate signals or other events that only
+work in the default loop by registering the signal watcher with the
+default loop and triggering an C<ev_async> watcher from the default loop
+watcher callback into the event loop interested in the signal.
+
+=back
+
+See also L</THREAD LOCKING EXAMPLE>.
+
+=head3 COROUTINES
+
+Libev is very accommodating to coroutines ("cooperative threads"):
+libev fully supports nesting calls to its functions from different
+coroutines (e.g. you can call C<ev_run> on the same loop from two
+different coroutines, and switch freely between both coroutines running
+the loop, as long as you don't confuse yourself). The only exception is
+that you must not do this from C<ev_periodic> reschedule callbacks.
+
+Care has been taken to ensure that libev does not keep local state inside
+C<ev_run>, and other calls do not usually allow for coroutine switches as
+they do not call any callbacks.
+
+=head2 COMPILER WARNINGS
+
+Depending on your compiler and compiler settings, you might get no or a
+lot of warnings when compiling libev code. Some people are apparently
+scared by this.
+
+However, these are unavoidable for many reasons. For one, each compiler
+has different warnings, and each user has different tastes regarding
+warning options. "Warn-free" code therefore cannot be a goal except when
+targeting a specific compiler and compiler-version.
+
+Another reason is that some compiler warnings require elaborate
+workarounds, or other changes to the code that make it less clear and less
+maintainable.
+
+And of course, some compiler warnings are just plain stupid, or simply
+wrong (because they don't actually warn about the condition their message
+seems to warn about). For example, certain older gcc versions had some
+warnings that resulted in an extreme number of false positives. These have
+been fixed, but some people still insist on making code warn-free with
+such buggy versions.
+
+While libev is written to generate as few warnings as possible,
+"warn-free" code is not a goal, and it is recommended not to build libev
+with any compiler warnings enabled unless you are prepared to cope with
+them (e.g. by ignoring them). Remember that warnings are just that:
+warnings, not errors, or proof of bugs.
+
+
+=head2 VALGRIND
+
+Valgrind has a special section here because it is a popular tool that is
+highly useful. Unfortunately, valgrind reports are very hard to interpret.
+
+If you think you found a bug (memory leak, uninitialised data access etc.)
+in libev, then check twice: If valgrind reports something like:
+
+ ==2274== definitely lost: 0 bytes in 0 blocks.
+ ==2274== possibly lost: 0 bytes in 0 blocks.
+ ==2274== still reachable: 256 bytes in 1 blocks.
+
+Then there is no memory leak, just as memory accounted to global variables
+is not a memleak - the memory is still being referenced, and didn't leak.
+
+Similarly, under some circumstances, valgrind might report kernel bugs
+as if it were a bug in libev (e.g. in realloc or in the poll backend,
+although an acceptable workaround has been found here), or it might be
+confused.
+
+Keep in mind that valgrind is a very good tool, but only a tool. Don't
+make it into some kind of religion.
+
+If you are unsure about something, feel free to contact the mailing list
+with the full valgrind report and an explanation on why you think this
+is a bug in libev (best check the archives, too :). However, don't be
+annoyed when you get a brisk "this is no bug" answer and take the chance
+of learning how to interpret valgrind properly.
+
+If you need, for some reason, empty reports from valgrind for your project
+I suggest using suppression lists.
+
+
+=head1 PORTABILITY NOTES
+
+=head2 GNU/LINUX 32 BIT LIMITATIONS
+
+GNU/Linux is the only common platform that supports 64 bit file/large file
+interfaces but I<disables> them by default.
+
+That means that libev compiled in the default environment doesn't support
+files larger than 2GiB or so, which mainly affects C<ev_stat> watchers.
+
+Unfortunately, many programs try to work around this GNU/Linux issue
+by enabling the large file API, which makes them incompatible with the
+standard libev compiled for their system.
+
+Likewise, libev cannot enable the large file API itself as this would
+suddenly make it incompatible to the default compile time environment,
+i.e. all programs not using special compile switches.
+
+=head2 OS/X AND DARWIN BUGS
+
+The whole thing is a bug if you ask me - basically any system interface
+you touch is broken, whether it is locales, poll, kqueue or even the
+OpenGL drivers.
+
+=head3 C<kqueue> is buggy
+
+The kqueue syscall is broken in all known versions - most versions support
+only sockets, many support pipes.
+
+Libev tries to work around this by not using C<kqueue> by default on this
+rotten platform, but of course you can still ask for it when creating a
+loop - embedding a socket-only kqueue loop into a select-based one is
+probably going to work well.
+
+=head3 C<poll> is buggy
+
+Instead of fixing C<kqueue>, Apple replaced their (working) C<poll>
+implementation by something calling C<kqueue> internally around the 10.5.6
+release, so now C<kqueue> I<and> C<poll> are broken.
+
+Libev tries to work around this by not using C<poll> by default on
+this rotten platform, but of course you can still ask for it when creating
+a loop.
+
+=head3 C<select> is buggy
+
+All that's left is C<select>, and of course Apple found a way to fuck this
+one up as well: On OS/X, C<select> actively limits the number of file
+descriptors you can pass in to 1024 - your program suddenly crashes when
+you use more.
+
+There is an undocumented "workaround" for this - defining
+C<_DARWIN_UNLIMITED_SELECT>, which libev tries to use, so select I<should>
+work on OS/X.
+
+=head2 SOLARIS PROBLEMS AND WORKAROUNDS
+
+=head3 C<errno> reentrancy
+
+The default compile environment on Solaris is unfortunately so
+thread-unsafe that you can't even use components/libraries compiled
+without C<-D_REENTRANT> in a threaded program, which, of course, isn't
+defined by default. A valid, if stupid, implementation choice.
+
+If you want to use libev in threaded environments you have to make sure
+it's compiled with C<_REENTRANT> defined.
+
+=head3 Event port backend
+
+The scalable event interface for Solaris is called "event
+ports". Unfortunately, this mechanism is very buggy in all major
+releases. If you run into high CPU usage, your program freezes or you get
+a large number of spurious wakeups, make sure you have all the relevant
+and latest kernel patches applied. No, I don't know which ones, but there
+are multiple ones to apply, and afterwards, event ports actually work
+great.
+
+If you can't get it to work, you can try running the program by setting
+the environment variable C<LIBEV_FLAGS=3> to only allow C<poll> and
+C<select> backends.
+
+=head2 AIX POLL BUG
+
+AIX unfortunately has a broken C<poll.h> header. Libev works around
+this by trying to avoid the poll backend altogether (i.e. it's not even
+compiled in), which normally isn't a big problem as C<select> works fine
+with large bitsets on AIX, and AIX is dead anyway.
+
+=head2 WIN32 PLATFORM LIMITATIONS AND WORKAROUNDS
+
+=head3 General issues
+
+Win32 doesn't support any of the standards (e.g. POSIX) that libev
+requires, and its I/O model is fundamentally incompatible with the POSIX
+model. Libev still offers limited functionality on this platform in
+the form of the C<EVBACKEND_SELECT> backend, and only supports socket
+descriptors. This only applies when using Win32 natively, not when using
+e.g. cygwin. Actually, it only applies to the microsofts own compilers,
+as every compiler comes with a slightly differently broken/incompatible
+environment.
+
+Lifting these limitations would basically require the full
+re-implementation of the I/O system. If you are into this kind of thing,
+then note that glib does exactly that for you in a very portable way (note
+also that glib is the slowest event library known to man).
+
+There is no supported compilation method available on windows except
+embedding it into other applications.
+
+Sensible signal handling is officially unsupported by Microsoft - libev
+tries its best, but under most conditions, signals will simply not work.
+
+Not a libev limitation but worth mentioning: windows apparently doesn't
+accept large writes: instead of resulting in a partial write, windows will
+either accept everything or return C<ENOBUFS> if the buffer is too large,
+so make sure you only write small amounts into your sockets (less than a
+megabyte seems safe, but this apparently depends on the amount of memory
+available).
+
+Due to the many, low, and arbitrary limits on the win32 platform and
+the abysmal performance of winsockets, using a large number of sockets
+is not recommended (and not reasonable). If your program needs to use
+more than a hundred or so sockets, then likely it needs to use a totally
+different implementation for windows, as libev offers the POSIX readiness
+notification model, which cannot be implemented efficiently on windows
+(due to Microsoft monopoly games).
+
+A typical way to use libev under windows is to embed it (see the embedding
+section for details) and use the following F<evwrap.h> header file instead
+of F<ev.h>:
+
+ #define EV_STANDALONE /* keeps ev from requiring config.h */
+ #define EV_SELECT_IS_WINSOCKET 1 /* configure libev for windows select */
+
+ #include "ev.h"
+
+And compile the following F<evwrap.c> file into your project (make sure
+you do I<not> compile the F<ev.c> or any other embedded source files!):
+
+ #include "evwrap.h"
+ #include "ev.c"
+
+=head3 The winsocket C<select> function
+
+The winsocket C<select> function doesn't follow POSIX in that it
+requires socket I<handles> and not socket I<file descriptors> (it is
+also extremely buggy). This makes select very inefficient, and also
+requires a mapping from file descriptors to socket handles (the Microsoft
+C runtime provides the function C<_open_osfhandle> for this). See the
+discussion of the C<EV_SELECT_USE_FD_SET>, C<EV_SELECT_IS_WINSOCKET> and
+C<EV_FD_TO_WIN32_HANDLE> preprocessor symbols for more info.
+
+The configuration for a "naked" win32 using the Microsoft runtime
+libraries and raw winsocket select is:
+
+ #define EV_USE_SELECT 1
+ #define EV_SELECT_IS_WINSOCKET 1 /* forces EV_SELECT_USE_FD_SET, too */
+
+Note that winsockets handling of fd sets is O(n), so you can easily get a
+complexity in the O(n²) range when using win32.
+
+=head3 Limited number of file descriptors
+
+Windows has numerous arbitrary (and low) limits on things.
+
+Early versions of winsocket's select only supported waiting for a maximum
+of C<64> handles (probably owning to the fact that all windows kernels
+can only wait for C<64> things at the same time internally; Microsoft
+recommends spawning a chain of threads and wait for 63 handles and the
+previous thread in each. Sounds great!).
+
+Newer versions support more handles, but you need to define C<FD_SETSIZE>
+to some high number (e.g. C<2048>) before compiling the winsocket select
+call (which might be in libev or elsewhere, for example, perl and many
+other interpreters do their own select emulation on windows).
+
+Another limit is the number of file descriptors in the Microsoft runtime
+libraries, which by default is C<64> (there must be a hidden I<64>
+fetish or something like this inside Microsoft). You can increase this
+by calling C<_setmaxstdio>, which can increase this limit to C<2048>
+(another arbitrary limit), but is broken in many versions of the Microsoft
+runtime libraries. This might get you to about C<512> or C<2048> sockets
+(depending on windows version and/or the phase of the moon). To get more,
+you need to wrap all I/O functions and provide your own fd management, but
+the cost of calling select (O(n²)) will likely make this unworkable.
+
+=head2 PORTABILITY REQUIREMENTS
+
+In addition to a working ISO-C implementation and of course the
+backend-specific APIs, libev relies on a few additional extensions:
+
+=over 4
+
+=item C<void (*)(ev_watcher_type *, int revents)> must have compatible
+calling conventions regardless of C<ev_watcher_type *>.
+
+Libev assumes not only that all watcher pointers have the same internal
+structure (guaranteed by POSIX but not by ISO C for example), but it also
+assumes that the same (machine) code can be used to call any watcher
+callback: The watcher callbacks have different type signatures, but libev
+calls them using an C<ev_watcher *> internally.
+
+=item null pointers and integer zero are represented by 0 bytes
+
+Libev uses C<memset> to initialise structs and arrays to C<0> bytes, and
+relies on this setting pointers and integers to null.
+
+=item pointer accesses must be thread-atomic
+
+Accessing a pointer value must be atomic, it must both be readable and
+writable in one piece - this is the case on all current architectures.
+
+=item C<sig_atomic_t volatile> must be thread-atomic as well
+
+The type C<sig_atomic_t volatile> (or whatever is defined as
+C<EV_ATOMIC_T>) must be atomic with respect to accesses from different
+threads. This is not part of the specification for C<sig_atomic_t>, but is
+believed to be sufficiently portable.
+
+=item C<sigprocmask> must work in a threaded environment
+
+Libev uses C<sigprocmask> to temporarily block signals. This is not
+allowed in a threaded program (C<pthread_sigmask> has to be used). Typical
+pthread implementations will either allow C<sigprocmask> in the "main
+thread" or will block signals process-wide, both behaviours would
+be compatible with libev. Interaction between C<sigprocmask> and
+C<pthread_sigmask> could complicate things, however.
+
+The most portable way to handle signals is to block signals in all threads
+except the initial one, and run the signal handling loop in the initial
+thread as well.
+
+=item C<long> must be large enough for common memory allocation sizes
+
+To improve portability and simplify its API, libev uses C<long> internally
+instead of C<size_t> when allocating its data structures. On non-POSIX
+systems (Microsoft...) this might be unexpectedly low, but is still at
+least 31 bits everywhere, which is enough for hundreds of millions of
+watchers.
+
+=item C<double> must hold a time value in seconds with enough accuracy
+
+The type C<double> is used to represent timestamps. It is required to
+have at least 51 bits of mantissa (and 9 bits of exponent), which is
+good enough for at least into the year 4000 with millisecond accuracy
+(the design goal for libev). This requirement is overfulfilled by
+implementations using IEEE 754, which is basically all existing ones.
+
+With IEEE 754 doubles, you get microsecond accuracy until at least the
+year 2255 (and millisecond accuracy till the year 287396 - by then, libev
+is either obsolete or somebody patched it to use C<long double> or
+something like that, just kidding).
+
+=back
+
+If you know of other additional requirements drop me a note.
+
+
+=head1 ALGORITHMIC COMPLEXITIES
+
+In this section the complexities of (many of) the algorithms used inside
+libev will be documented. For complexity discussions about backends see
+the documentation for C<ev_default_init>.
+
+All of the following are about amortised time: If an array needs to be
+extended, libev needs to realloc and move the whole array, but this
+happens asymptotically rarer with higher number of elements, so O(1) might
+mean that libev does a lengthy realloc operation in rare cases, but on
+average it is much faster and asymptotically approaches constant time.
+
+=over 4
+
+=item Starting and stopping timer/periodic watchers: O(log skipped_other_timers)
+
+This means that, when you have a watcher that triggers in one hour and
+there are 100 watchers that would trigger before that, then inserting will
+have to skip roughly seven (C<ld 100>) of these watchers.
+
+=item Changing timer/periodic watchers (by autorepeat or calling again): O(log skipped_other_timers)
+
+That means that changing a timer costs less than removing/adding them,
+as only the relative motion in the event queue has to be paid for.
+
+=item Starting io/check/prepare/idle/signal/child/fork/async watchers: O(1)
+
+These just add the watcher into an array or at the head of a list.
+
+=item Stopping check/prepare/idle/fork/async watchers: O(1)
+
+=item Stopping an io/signal/child watcher: O(number_of_watchers_for_this_(fd/signal/pid % EV_PID_HASHSIZE))
+
+These watchers are stored in lists, so they need to be walked to find the
+correct watcher to remove. The lists are usually short (you don't usually
+have many watchers waiting for the same fd or signal: one is typical, two
+is rare).
+
+=item Finding the next timer in each loop iteration: O(1)
+
+By virtue of using a binary or 4-heap, the next timer is always found at a
+fixed position in the storage array.
+
+=item Each change on a file descriptor per loop iteration: O(number_of_watchers_for_this_fd)
+
+A change means an I/O watcher gets started or stopped, which requires
+libev to recalculate its status (and possibly tell the kernel, depending
+on backend and whether C<ev_io_set> was used).
+
+=item Activating one watcher (putting it into the pending state): O(1)
+
+=item Priority handling: O(number_of_priorities)
+
+Priorities are implemented by allocating some space for each
+priority. When doing priority-based operations, libev usually has to
+linearly search all the priorities, but starting/stopping and activating
+watchers becomes O(1) with respect to priority handling.
+
+=item Sending an ev_async: O(1)
+
+=item Processing ev_async_send: O(number_of_async_watchers)
+
+=item Processing signals: O(max_signal_number)
+
+Sending involves a system call I<iff> there were no other C<ev_async_send>
+calls in the current loop iteration and the loop is currently
+blocked. Checking for async and signal events involves iterating over all
+running async watchers or all signal numbers.
+
+=back
+
+
+=head1 PORTING FROM LIBEV 3.X TO 4.X
+
+The major version 4 introduced some incompatible changes to the API.
+
+At the moment, the C<ev.h> header file provides compatibility definitions
+for all changes, so most programs should still compile. The compatibility
+layer might be removed in later versions of libev, so better update to the
+new API early than late.
+
+=over 4
+
+=item C<EV_COMPAT3> backwards compatibility mechanism
+
+The backward compatibility mechanism can be controlled by
+C<EV_COMPAT3>. See L</"PREPROCESSOR SYMBOLS/MACROS"> in the L</EMBEDDING>
+section.
+
+=item C<ev_default_destroy> and C<ev_default_fork> have been removed
+
+These calls can be replaced easily by their C<ev_loop_xxx> counterparts:
+
+ ev_loop_destroy (EV_DEFAULT_UC);
+ ev_loop_fork (EV_DEFAULT);
+
+=item function/symbol renames
+
+A number of functions and symbols have been renamed:
+
+ ev_loop => ev_run
+ EVLOOP_NONBLOCK => EVRUN_NOWAIT
+ EVLOOP_ONESHOT => EVRUN_ONCE
+
+ ev_unloop => ev_break
+ EVUNLOOP_CANCEL => EVBREAK_CANCEL
+ EVUNLOOP_ONE => EVBREAK_ONE
+ EVUNLOOP_ALL => EVBREAK_ALL
+
+ EV_TIMEOUT => EV_TIMER
+
+ ev_loop_count => ev_iteration
+ ev_loop_depth => ev_depth
+ ev_loop_verify => ev_verify
+
+Most functions working on C<struct ev_loop> objects don't have an
+C<ev_loop_> prefix, so it was removed; C<ev_loop>, C<ev_unloop> and
+associated constants have been renamed to not collide with the C<struct
+ev_loop> anymore and C<EV_TIMER> now follows the same naming scheme
+as all other watcher types. Note that C<ev_loop_fork> is still called
+C<ev_loop_fork> because it would otherwise clash with the C<ev_fork>
+typedef.
+
+=item C<EV_MINIMAL> mechanism replaced by C<EV_FEATURES>
+
+The preprocessor symbol C<EV_MINIMAL> has been replaced by a different
+mechanism, C<EV_FEATURES>. Programs using C<EV_MINIMAL> usually compile
+and work, but the library code will of course be larger.
+
+=back
+
+
+=head1 GLOSSARY
+
+=over 4
+
+=item active
+
+A watcher is active as long as it has been started and not yet stopped.
+See L</WATCHER STATES> for details.
+
+=item application
+
+In this document, an application is whatever is using libev.
+
+=item backend
+
+The part of the code dealing with the operating system interfaces.
+
+=item callback
+
+The address of a function that is called when some event has been
+detected. Callbacks are being passed the event loop, the watcher that
+received the event, and the actual event bitset.
+
+=item callback/watcher invocation
+
+The act of calling the callback associated with a watcher.
+
+=item event
+
+A change of state of some external event, such as data now being available
+for reading on a file descriptor, time having passed or simply not having
+any other events happening anymore.
+
+In libev, events are represented as single bits (such as C<EV_READ> or
+C<EV_TIMER>).
+
+=item event library
+
+A software package implementing an event model and loop.
+
+=item event loop
+
+An entity that handles and processes external events and converts them
+into callback invocations.
+
+=item event model
+
+The model used to describe how an event loop handles and processes
+watchers and events.
+
+=item pending
+
+A watcher is pending as soon as the corresponding event has been
+detected. See L</WATCHER STATES> for details.
+
+=item real time
+
+The physical time that is observed. It is apparently strictly monotonic :)
+
+=item wall-clock time
+
+The time and date as shown on clocks. Unlike real time, it can actually
+be wrong and jump forwards and backwards, e.g. when you adjust your
+clock.
+
+=item watcher
+
+A data structure that describes interest in certain events. Watchers need
+to be started (attached to an event loop) before they can receive events.
+
+=back
+
+=head1 AUTHOR
+
+Marc Lehmann <libev@schmorp.de>, with repeated corrections by Mikael
+Magnusson and Emanuele Giaquinta, and minor corrections by many others.
+
--- rxvt-unicode/libev/ev_poll.c
+++ rxvt-unicode/libev/ev_poll.c
@@ -39,7 +39,8 @@
#include <poll.h>
-void inline_size
+inline_size
+void
pollidx_init (int *base, int count)
{
/* consider using memset (.., -1, ...), which is practically guaranteed
@@ -126,7 +127,8 @@
}
}
-int inline_size
+inline_size
+int
poll_init (EV_P_ int flags)
{
backend_mintime = 1e-3;
@@ -139,7 +141,8 @@
return EVBACKEND_POLL;
}
-void inline_size
+inline_size
+void
poll_destroy (EV_P)
{
ev_free (pollidxs);
--- rxvt-unicode/libev/ev_port.c
+++ rxvt-unicode/libev/ev_port.c
@@ -55,7 +55,8 @@
#include <string.h>
#include <errno.h>
-void inline_speed
+inline_speed
+void
port_associate_and_check (EV_P_ int fd, int ev)
{
if (0 >
@@ -136,7 +137,8 @@
}
}
-int inline_size
+inline_size
+int
port_init (EV_P_ int flags)
{
/* Initialize the kernel queue */
@@ -163,13 +165,15 @@
return EVBACKEND_PORT;
}
-void inline_size
+inline_size
+void
port_destroy (EV_P)
{
ev_free (port_events);
}
-void inline_size
+inline_size
+void
port_fork (EV_P)
{
close (backend_fd);
--- rxvt-unicode/libev/ev_select.c
+++ rxvt-unicode/libev/ev_select.c
@@ -271,7 +271,8 @@
#endif
}
-int inline_size
+inline_size
+int
select_init (EV_P_ int flags)
{
backend_mintime = 1e-6;
@@ -300,7 +301,8 @@
return EVBACKEND_SELECT;
}
-void inline_size
+inline_size
+void
select_destroy (EV_P)
{
ev_free (vec_ri);
--- rxvt-unicode/libev/import_libevent
+++ rxvt-unicode/libev/import_libevent
@@ -0,0 +1,131 @@
+#!/bin/sh
+
+LE=../libevent-1.4.3-stable
+
+if ! [ -e evbuffer.c ]; then
+ echo do not run this programm unless you know what you are doing
+ exit 1
+fi
+
+# this program combines libev and libevent into a single package
+
+cvs update -AdP libev
+rsync -avP libev/. . --exclude CVS
+
+rm -f configure.ac
+
+cp $LE/evdns.h .
+
+perl -i -pe 's%^/.libevent-include./%#include "event_compat.h"%' event.h
+
+perl -ne '
+ s/\s+char buf\[64\];/\tchar buf[96];/;
+ if (/#include "event.h"/) {
+ print "#ifndef EV_STANDALONE\n$_#endif\n";
+ next;
+ }
+ if (/#include "misc.h"/) {
+ print "#ifndef EV_STANDALONE\n$_#endif\n";
+ next;
+ }
+ if (/#include "(unistd.h|sys\/time.h)"/) {
+ print "#ifndef WIN32\n$_#endif\n";
+ next;
+ }
+ next if /#include "log.h"/;
+
+ print;
+' <$LE/evdns.c >evdns.c
+
+cp $LE/autogen.sh .
+cp $LE/epoll_sub.c .
+cp $LE/evbuffer.c .
+cp $LE/buffer.c .
+cp $LE/evhttp.h .
+cp $LE/evutil.h .
+cp $LE/evutil.c .
+cp $LE/event-config.h .
+cp $LE/event-internal.h .
+cp $LE/evrpc.h .
+cp $LE/evrpc.c .
+cp $LE/evrpc-internal.h .
+cp $LE/http.c .
+cp $LE/event_tagging.c .
+cp $LE/http-internal.h .
+cp $LE/strlcpy-internal.h .
+cp $LE/log.c .
+cp $LE/log.h .
+cp $LE/strlcpy.c .
+rsync -a $LE/WIN32* $LE/sample $LE/test $LE/compat . --del
+#rename 's/libevent/libev/' WIN32-Prj/lib*
+cp $LE/aclocal.m4 .
+#cp $LE/acconfig.h .
+cp $LE/config.h.in .
+cp $LE/event_rpcgen.py .
+cp $LE/*.3 .
+
+#perl -i -pe 's/libevent/libev/g' sample/Makefile.am
+#perl -i -pe 's/libevent/libev/g' test/Makefile.am
+
+perl -i -pe 's/#include <event.h>$/#include "event.h"/' test/*.c
+
+perl -i -ne '
+ next if /"event-internal.h"/;
+ s/base\d?->sig.ev_signal_added/0/;
+ s/base\d?->sig.ev_signal_pair\[0\]/-1/;
+ s/base->sig.evsignal_caught/0/;
+ next if /^\ttest_signal_(dealloc|pipeloss|switchbase|assert|restore)\(\)/;
+ next if /^\ttest_simplesignal\(\)/; # non-default-loop
+ next if /^\ttest_immediatesignal\(\)/; # non-default-loop
+ next if /test_priorities\(\d\)/;
+ print;
+' test/regress.c
+
+perl -ne '
+ s/\bmin_heap.h\b//g;
+ s/\bsignal.c\b//g;
+ s/\bevport.c\b//g;
+ s/\bkqueue.c\b//g;
+ s/\bdevpoll.c\b//g;
+ s/\brtsig.c\b//g;
+ s/\bselect.c\b//g;
+ s/\bpoll.c\b//g;
+ s/\bepoll.c\b//g;
+ s/\bepoll_sub.c\b//g;
+ s/\bevent-internal.h\b//g;
+ s/\bevsignal.h\b//g;
+ s/^(man_MANS\s*=)/$1 ev.3 /;
+ s/^(EXTRA_DIST\s*=)/$1 libev.m4 ev.h ev_vars.h ev_wrap.h event_compat.h ev++.h ev_epoll.c ev_select.c ev_poll.c ev_kqueue.c ev_port.c ev_win32.c ev.3 ev.pod /;
+ s/^(include_HEADERS\s*=)/$1 ev.h event_compat.h ev++.h /;
+ s/^(CORE_SRC\s*=)/$1 ev.c /;
+ s/^(SYS_LIBS\s*=)/$1 -lm /;
+ #s/libevent/libev/g;
+ print;
+' <$LE/Makefile.am >Makefile.am
+
+perl -ne '
+ #s/-Wall/-Wall -Wno-comment -Wunused-function -Wno-unused-value/;
+ s/-Wall//g;
+ #s/libevent/libev/g;
+ #VERSION
+ s/AM_INIT_AUTOMAKE\s*\(.*,(.*)\)/AM_INIT_AUTOMAKE(libevent-$1+libev,3.1)/;
+ s/AC_LIBOBJ\(select\)/: ;/g;
+ s/AC_LIBOBJ\(poll\)/: ;/g;
+ s/AC_LIBOBJ\(kqueue\)/: ;/g;
+ s/AC_LIBOBJ\(epoll\)/: ;/g;
+ s/AC_LIBOBJ\(devpoll\)/: ;/g;
+ s/AC_LIBOBJ\(evport\)/: ;/g;
+ s/AC_LIBOBJ\(signal\)/: ;/g;
+ s/AC_LIBOBJ\(rtsig\)/: ;/g;
+ print "m4_include([libev.m4])\n" if /^AC_OUTPUT/;
+ print;
+' <$LE/configure.in >configure.in
+
+aclocal-1.7
+automake-1.7 --add-missing
+autoconf
+autoheader
+libtoolize
+CC="ccache gcc" ./configure --prefix=/opt/libev --disable-shared "$@"
+
+
--- rxvt-unicode/libev/LICENSE
+++ rxvt-unicode/libev/LICENSE
@@ -0,0 +1,37 @@
+All files in libev are
+Copyright (c)2007,2008,2009,2010,2011,2012,2013 Marc Alexander Lehmann.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above
+ copyright notice, this list of conditions and the following
+ disclaimer in the documentation and/or other materials provided
+ with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+Alternatively, the contents of this package may be used under the terms
+of the GNU General Public License ("GPL") version 2 or any later version,
+in which case the provisions of the GPL are applicable instead of the
+above. If you wish to allow the use of your version of this package only
+under the terms of the GPL and not to allow others to use your version of
+this file under the BSD license, indicate your decision by deleting the
+provisions above and replace them with the notice and other provisions
+required by the GPL in this and the other files of this package. If you do
+not delete the provisions above, a recipient may use your version of this
+file under either the BSD or the GPL.
--- rxvt-unicode/libev/Makefile.am
+++ rxvt-unicode/libev/Makefile.am
@@ -0,0 +1,20 @@
+AUTOMAKE_OPTIONS = foreign
+
+VERSION_INFO = 4:0:0
+
+EXTRA_DIST = LICENSE Changes libev.m4 autogen.sh \
+ ev_vars.h ev_wrap.h \
+ ev_epoll.c ev_select.c ev_poll.c ev_kqueue.c ev_port.c ev_win32.c \
+ ev.3 ev.pod Symbols.ev Symbols.event
+
+man_MANS = ev.3
+
+include_HEADERS = ev.h ev++.h event.h
+
+lib_LTLIBRARIES = libev.la
+
+libev_la_SOURCES = ev.c event.c
+libev_la_LDFLAGS = -version-info $(VERSION_INFO)
+
+ev.3: ev.pod
+ pod2man -n LIBEV -r "libev-$(VERSION)" -c "libev - high performance full featured event loop" -s3 <$< >$@
--- rxvt-unicode/libev/README
+++ rxvt-unicode/libev/README
@@ -0,0 +1,58 @@
+libev is a high-performance event loop/event model with lots of features.
+(see benchmark at http://libev.schmorp.de/bench.html)
+
+
+ABOUT
+
+ Homepage: http://software.schmorp.de/pkg/libev
+ Mailinglist: libev@lists.schmorp.de
+ http://lists.schmorp.de/cgi-bin/mailman/listinfo/libev
+ Library Documentation: http://pod.tst.eu/http://cvs.schmorp.de/libev/ev.pod
+
+ Libev is modelled (very losely) after libevent and the Event perl
+ module, but is faster, scales better and is more correct, and also more
+ featureful. And also smaller. Yay.
+
+ Some of the specialties of libev not commonly found elsewhere are:
+
+ - extensive and detailed, readable documentation (not doxygen garbage).
+ - fully supports fork, can detect fork in various ways and automatically
+ re-arms kernel mechanisms that do not support fork.
+ - highly optimised select, poll, epoll, kqueue and event ports backends.
+ - filesystem object (path) watching (with optional linux inotify support).
+ - wallclock-based times (using absolute time, cron-like).
+ - relative timers/timeouts (handle time jumps).
+ - fast intra-thread communication between multiple
+ event loops (with optional fast linux eventfd backend).
+ - extremely easy to embed (fully documented, no dependencies,
+ autoconf supported but optional).
+ - very small codebase, no bloated library, simple code.
+ - fully extensible by being able to plug into the event loop,
+ integrate other event loops, integrate other event loop users.
+ - very little memory use (small watchers, small event loop data).
+ - optional C++ interface allowing method and function callbacks
+ at no extra memory or runtime overhead.
+ - optional Perl interface with similar characteristics (capable
+ of running Glib/Gtk2 on libev).
+ - support for other languages (multiple C++ interfaces, D, Ruby,
+ Python) available from third-parties.
+
+ Examples of programs that embed libev: the EV perl module, node.js,
+ auditd, rxvt-unicode, gvpe (GNU Virtual Private Ethernet), the
+ Deliantra MMORPG server (http://www.deliantra.net/), Rubinius (a
+ next-generation Ruby VM), the Ebb web server, the Rev event toolkit.
+
+
+CONTRIBUTORS
+
+ libev was written and designed by Marc Lehmann and Emanuele Giaquinta.
+
+ The following people sent in patches or made other noteworthy
+ contributions to the design (for minor patches, see the Changes
+ file. If I forgot to include you, please shout at me, it was an
+ accident):
+
+ W.C.A. Wijngaards
+ Christopher Layne
+ Chris Brody
+
--- rxvt-unicode/libev/README.embed
+++ rxvt-unicode/libev/README.embed
@@ -0,0 +1,3 @@
+This file is now included in the main libev documentation, see
+
+ http://cvs.schmorp.de/libev/ev.html
--- rxvt-unicode/libev/Symbols.ev
+++ rxvt-unicode/libev/Symbols.ev
@@ -0,0 +1,73 @@
+ev_async_send
+ev_async_start
+ev_async_stop
+ev_backend
+ev_break
+ev_check_start
+ev_check_stop
+ev_child_start
+ev_child_stop
+ev_cleanup_start
+ev_cleanup_stop
+ev_clear_pending
+ev_default_loop
+ev_default_loop_ptr
+ev_depth
+ev_embed_start
+ev_embed_stop
+ev_embed_sweep
+ev_embeddable_backends
+ev_feed_event
+ev_feed_fd_event
+ev_feed_signal
+ev_feed_signal_event
+ev_fork_start
+ev_fork_stop
+ev_idle_start
+ev_idle_stop
+ev_invoke
+ev_invoke_pending
+ev_io_start
+ev_io_stop
+ev_iteration
+ev_loop_destroy
+ev_loop_fork
+ev_loop_new
+ev_now
+ev_now_update
+ev_once
+ev_pending_count
+ev_periodic_again
+ev_periodic_start
+ev_periodic_stop
+ev_prepare_start
+ev_prepare_stop
+ev_recommended_backends
+ev_ref
+ev_resume
+ev_run
+ev_set_allocator
+ev_set_invoke_pending_cb
+ev_set_io_collect_interval
+ev_set_loop_release_cb
+ev_set_syserr_cb
+ev_set_timeout_collect_interval
+ev_set_userdata
+ev_signal_start
+ev_signal_stop
+ev_sleep
+ev_stat_start
+ev_stat_stat
+ev_stat_stop
+ev_supported_backends
+ev_suspend
+ev_time
+ev_timer_again
+ev_timer_remaining
+ev_timer_start
+ev_timer_stop
+ev_unref
+ev_userdata
+ev_verify
+ev_version_major
+ev_version_minor
--- rxvt-unicode/libev/Symbols.event
+++ rxvt-unicode/libev/Symbols.event
@@ -0,0 +1,24 @@
+event_active
+event_add
+event_base_dispatch
+event_base_free
+event_base_get_method
+event_base_loop
+event_base_loopexit
+event_base_new
+event_base_once
+event_base_priority_init
+event_base_set
+event_del
+event_dispatch
+event_get_callback
+event_get_method
+event_get_version
+event_init
+event_loop
+event_loopexit
+event_once
+event_pending
+event_priority_init
+event_priority_set
+event_set
--- rxvt-unicode/libev/update_ev_c
+++ rxvt-unicode/libev/update_ev_c
@@ -0,0 +1,8 @@
+#!/bin/sh -e
+
+(
+ sed -ne '1,\%/\* ECB.H BEGIN \*/%p' ev.c
+ cat ~/src/libecb/ecb.h
+ sed -ne '\%/\* ECB.H END \*/%,$p' ev.c
+) >ev.c~ && mv ev.c~ ev.c
+
--- rxvt-unicode/libev/update_ev_wrap
+++ rxvt-unicode/libev/update_ev_wrap
@@ -0,0 +1,19 @@
+#!/bin/sh
+
+(
+ echo '#define VAR(name,decl) name'
+ echo '#define EV_GENWRAP 1'
+ cat ev_vars.h
+) | cc -E -o - - | perl -ne '
+ while (<>) {
+ push @syms, $1 if /(^\w+)/;
+ }
+ print "/* DO NOT EDIT, automatically generated by update_ev_wrap */\n",
+ "#ifndef EV_WRAP_H\n",
+ "#define EV_WRAP_H\n",
+ (map "#define $_ ((loop)->$_)\n", sort @syms),
+ "#else\n",
+ "#undef EV_WRAP_H\n",
+ (map "#undef $_\n", sort @syms),
+ "#endif\n";
+' >ev_wrap.h
--- rxvt-unicode/libev/update_symbols
+++ rxvt-unicode/libev/update_symbols
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+make ev.o event.o || exit
+
+nm ev.o | perl -ne 'print "$1\n" if /\S+ [A-Z] (\S+)/' > Symbols.ev
+nm event.o | perl -ne 'print "$1\n" if /\S+ [A-Z] (\S+)/' > Symbols.event
+
--- rxvt-unicode/libptytty/autogen.sh
+++ rxvt-unicode/libptytty/autogen.sh
@@ -0,0 +1,6 @@
+#! /bin/sh
+
+if autoreconf -i; then
+ rm -rf autom4te.cache
+ echo "Now run ./configure"
+fi
--- rxvt-unicode/libptytty/Changes
+++ rxvt-unicode/libptytty/Changes
@@ -1,3 +1,4 @@
+1.8 Thu Feb 25 21:17:12 CET 2016
- fix m4 underquoting bug that prevented utmpx detection from
working on systems without the utmp.h header, such as
freebsd 9 and newer.
--- rxvt-unicode/libptytty/configure.ac
+++ rxvt-unicode/libptytty/configure.ac
@@ -0,0 +1,26 @@
+dnl#
+dnl# Process this file with autoconf to produce a configure script.
+dnl#
+
+AC_INIT(libptytty,1.8)
+AM_INIT_AUTOMAKE
+AC_CONFIG_HEADER(config.h:config.h.in)
+
+AC_CANONICAL_HOST
+
+AC_PROG_CXX
+AC_PROG_INSTALL
+AC_PROG_LIBTOOL
+
+AC_LANG(C++)
+
+PTY_CHECK
+
+TTY_GROUP_CHECK
+
+UTMP_CHECK
+
+SCM_RIGHTS_CHECK
+
+AC_CONFIG_FILES([Makefile])
+AC_OUTPUT
--- rxvt-unicode/libptytty/COPYING
+++ rxvt-unicode/libptytty/COPYING
@@ -0,0 +1,340 @@
+ GNU GENERAL PUBLIC LICENSE
+ Version 2, June 1991
+
+ Copyright (C) 1989, 1991 Free Software Foundation, Inc.
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+ Preamble
+
+ The licenses for most software are designed to take away your
+freedom to share and change it. By contrast, the GNU General Public
+License is intended to guarantee your freedom to share and change free
+software--to make sure the software is free for all its users. This
+General Public License applies to most of the Free Software
+Foundation's software and to any other program whose authors commit to
+using it. (Some other Free Software Foundation software is covered by
+the GNU Library General Public License instead.) You can apply it to
+your programs, too.
+
+ When we speak of free software, we are referring to freedom, not
+price. Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+this service if you wish), that you receive source code or can get it
+if you want it, that you can change the software or use pieces of it
+in new free programs; and that you know you can do these things.
+
+ To protect your rights, we need to make restrictions that forbid
+anyone to deny you these rights or to ask you to surrender the rights.
+These restrictions translate to certain responsibilities for you if you
+distribute copies of the software, or if you modify it.
+
+ For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must give the recipients all the rights that
+you have. You must make sure that they, too, receive or can get the
+source code. And you must show them these terms so they know their
+rights.
+
+ We protect your rights with two steps: (1) copyright the software, and
+(2) offer you this license which gives you legal permission to copy,
+distribute and/or modify the software.
+
+ Also, for each author's protection and ours, we want to make certain
+that everyone understands that there is no warranty for this free
+software. If the software is modified by someone else and passed on, we
+want its recipients to know that what they have is not the original, so
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+
+ Finally, any free program is threatened constantly by software
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+
+ The precise terms and conditions for copying, distribution and
+modification follow.
+
+ GNU GENERAL PUBLIC LICENSE
+ TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. This License applies to any program or other work which contains
+a notice placed by the copyright holder saying it may be distributed
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+the term "modification".) Each licensee is addressed as "you".
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+Activities other than copying, distribution and modification are not
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+
+ 1. You may copy and distribute verbatim copies of the Program's
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+
+You may charge a fee for the physical act of transferring a copy, and
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--- rxvt-unicode/libptytty/doc/libptytty.3
+++ rxvt-unicode/libptytty/doc/libptytty.3
@@ -0,0 +1,383 @@
+.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.30)
+.\"
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+.\}
+.rr rF
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+. \" fudge factors for nroff and troff
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+. ds ~ ~
+. ds /
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+.if t \{\
+. ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
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+. ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
+. ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
+. ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
+. ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
+.\}
+. \" troff and (daisy-wheel) nroff accents
+.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
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+.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
+.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
+.ds ae a\h'-(\w'a'u*4/10)'e
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+. \" corrections for vroff
+.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
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+. \" for low resolution devices (crt and lpr)
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+\{\
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+.\}
+.rm #[ #] #H #V #F C
+.\" ========================================================================
+.\"
+.IX Title "libptytty 3"
+.TH libptytty 3 "2016-02-25" "1.8" "LIBPTYTTY"
+.\" For nroff, turn off justification. Always turn off hyphenation; it makes
+.\" way too many mistakes in technical documents.
+.if n .ad l
+.nh
+.SH "NAME"
+libptytty \- OS independent and secure pty/tty and utmp/wtmp/lastlog handling
+.SH "SYNOPSIS"
+.IX Header "SYNOPSIS"
+.Vb 1
+\& cc ... \-lptytty
+\&
+\& #include <libptytty.h>
+\&
+\&
+\& // C++
+\& ptytty *pty = ptytty::create ();
+\&
+\& if (!pty\->get ())
+\& // error allocating pty
+\&
+\& if (we want utmp)
+\& pty\->login (process_pid, 0, "remote.host");
+\& else if (we want utmp AND wtmp/lastlog)
+\& pty\->login (process_pid, 1, "remote.host");
+\&
+\& // we are done with it
+\& delete pty;
+\&
+\&
+\& // C
+\& PTYTTY pty = ptytty_create ();
+\&
+\& if (!ptytty_get (pty))
+\& // error allocating pty
+\&
+\& if (we want utmp)
+\& ptytty_login (pty, process_pid, 0, "remote.host");
+\& else if (we want utmp AND wtmp/lastlog)
+\& ptytty_login (pty, process_pid, 1, "remote.host");
+\&
+\& // we are done with it
+\& ptytty_delete (pty);
+.Ve
+.PP
+See also the \fIeg/\fR directory, which currently contains the \fIc\-sample.c\fR
+file that spawns a login shell from C using libptytty.
+.SH "DESCRIPTION"
+.IX Header "DESCRIPTION"
+Libptytty is a small library that offers pseudo-tty management in an
+OS-independent way. It was created out of frustration over the many
+differences of pty/tty handling in different operating systems for the use
+inside \f(CW\*(C`rxvt\-unicode\*(C'\fR.
+.PP
+In addition to offering mere pty/tty management, it also offers session
+database support (utmp and optional wtmp/lastlog updates for login
+shells).
+.PP
+It also supports fork'ing after startup and dropping privileges in the
+calling process, so in case the calling process gets compromised by the
+user starting the program there is less to gain, as only the helper
+process runs with privileges (e.g. setuid/setgid), which reduces the area
+of attack immensely.
+.PP
+Libptytty is written in \*(C+, but it also offers a C\-only \s-1API.\s0
+.SH "SECURITY CONSIDERATIONS"
+.IX Header "SECURITY CONSIDERATIONS"
+\&\fI\f(BIIt is of paramount importance that you at least read the following
+paragraph!\fI\fR
+.PP
+If you write a typical terminal-like program that just wants one or more
+ptys, you should call the \f(CW\*(C`ptytty::init ()\*(C'\fR method (C: \f(CW\*(C`ptytty_init ()\*(C'\fR
+function) as the very first thing in your program:
+.PP
+.Vb 5
+\& int main (int argc, char *argv[])
+\& {
+\& // do nothing here
+\& ptytty::init ();
+\& // in C: ptytty_init ();
+\&
+\& // initialise, parse arguments, etc.
+\& }
+.Ve
+.PP
+This checks whether the program runs setuid or setgid. If yes then it will
+fork a helper process and drop privileges.
+.PP
+Some programs need finer control over if and when this helper process
+is started, and if and how to drop privileges. For those programs, the
+methods \f(CW\*(C`ptytty::use_helper\*(C'\fR and \f(CW\*(C`ptytty::drop_privileges\*(C'\fR (and possibly
+\&\f(CW\*(C`ptytty::sanitise_stdfd\*(C'\fR) are more useful.
+.SH "\*(C+ INTERFACE: THE ptytty CLASS"
+.IX Header " INTERFACE: THE ptytty CLASS"
+.SS "\s-1STATIC METHODS\s0"
+.IX Subsection "STATIC METHODS"
+.IP "ptytty::init ()" 4
+.IX Item "ptytty::init ()"
+The default way to initialise libptytty. Must be called immediately as
+the first thing in the \f(CW\*(C`main\*(C'\fR function, or earlier e.g. during static
+construction time. The earlier, the better.
+.Sp
+This method calls \f(CW\*(C`sanitise_stdfd\*(C'\fR and then checks whether the program runs
+with setuid/setgid permissions and, if yes, spawns a helper process for
+pty/tty management. It then drops the privileges completely, so the actual
+program runs without setuid/setgid privileges.
+.Sp
+On failure, this method terminates the process.
+.IP "ptytty::use_helper ()" 4
+.IX Item "ptytty::use_helper ()"
+Tries to start a helper process that retains privileges even when the
+calling process does not. This is usually called from \f(CW\*(C`ptytty::init\*(C'\fR when
+it detects that the program is running setuid or setgid, but can be called
+manually if it is inconvenient to drop privileges at startup, or when
+you are not running setuid/setgid but want to drop privileges (e.g. when
+running as a root-started daemon).
+.Sp
+This method will try not to start more than one helper process. The same
+helper process can usually be used both from the process starting it and
+all its fork'ed (not exec'ed) children.
+.Sp
+On failure, this method terminates the process.
+.IP "ptytty::drop_privileges ()" 4
+.IX Item "ptytty::drop_privileges ()"
+Drops privileges completely, i.e. sets real, effective and saved user
+id to the real user id. Useful to make sure that the process doesn't
+run with special privileges.
+.Sp
+On failure, this method terminates the process.
+.IP "ptytty::sanitise_stdfd ()" 4
+.IX Item "ptytty::sanitise_stdfd ()"
+Checks whether file descriptors 0, 1 and 2 (stdin, stdout and stderr)
+are valid (open) and, if not, connects them to \fI/dev/tty\fR or
+\&\fI/dev/null\fR if possible. This is necessary because libptytty might
+want to output error messages to those descriptors, which at the time
+of outputting the error message, might be connected to something
+unsuitable opened by the unsuspecting program itself (this can be a
+security issue).
+.Sp
+On failure, this method terminates the process.
+.IP "bool success = ptytty::send_fd (int socket, int fd)" 4
+.IX Item "bool success = ptytty::send_fd (int socket, int fd)"
+Utility method to send a file descriptor over a unix domain
+socket. Returns true if successful, false otherwise. This method is only
+exposed for your convenience and is not required for normal operation.
+.IP "int fd = ptytty::recv_fd (int socket)" 4
+.IX Item "int fd = ptytty::recv_fd (int socket)"
+Utility method to receive a file descriptor over a unix domain
+socket. Returns the fd if successful and \f(CW\*(C`\-1\*(C'\fR otherwise. This method
+is only exposed for your convenience and is not required for normal
+operation.
+.IP "ptytty *pty = ptytty::create ()" 4
+.IX Item "ptytty *pty = ptytty::create ()"
+Creates new ptytty object. Creation does not yet do anything besides
+allocating the structure.
+.Sp
+A static method is used because the actual ptytty implementation can
+differ at runtime, so you need a dynamic object creation facility.
+.SS "\s-1DYNAMIC/SESSION\-RELATED DATA MEMBERS AND METHODS\s0"
+.IX Subsection "DYNAMIC/SESSION-RELATED DATA MEMBERS AND METHODS"
+.IP "int pty_fd = pty\->pty" 4
+.IX Item "int pty_fd = pty->pty"
+.PD 0
+.IP "int tty_fd = pty\->tty" 4
+.IX Item "int tty_fd = pty->tty"
+.PD
+These members contain the pty and tty file descriptors, respectively. They
+initially contain \f(CW\*(C`\-1\*(C'\fR until a successful call to \f(CW\*(C`ptytty::get\*(C'\fR.
+.IP "bool success = pty\->get ()" 4
+.IX Item "bool success = pty->get ()"
+Tries to find, allocate and initialise a new pty/tty pair. Returns \f(CW\*(C`true\*(C'\fR
+when successful.
+.Sp
+If the helper process is running and there is a protocol error, this
+method terminates the process.
+.IP "pty\->login (int cmd_pid, bool login_shell, const char *hostname)" 4
+.IX Item "pty->login (int cmd_pid, bool login_shell, const char *hostname)"
+Creates an entry in the systems session database(s) (utmp, wtmp, lastlog).
+\&\f(CW\*(C`cmd_pid\*(C'\fR must be the pid of the process representing the session
+(such as the login shell), \f(CW\*(C`login_shell\*(C'\fR defines whether the session is
+associated with a login, which influences whether wtmp and lastlog entries
+are created, and \f(CW\*(C`hostname\*(C'\fR should identify the \*(L"hostname\*(R" the user logs
+in from, which often is the value of the \f(CW\*(C`DISPLAY\*(C'\fR variable or tty line
+in case of local logins.
+.Sp
+Calling this method is optional. A session starts at the time of the login
+call and extends until the ptytty object is destroyed.
+.IP "pty\->close_tty ()" 4
+.IX Item "pty->close_tty ()"
+Closes the tty. Useful after forking in the parent/pty process.
+.IP "bool success = pty\->make_controlling_tty ()" 4
+.IX Item "bool success = pty->make_controlling_tty ()"
+Tries to make the pty/tty pair the controlling terminal of the current
+process. Useful after forking in the child/tty process.
+.IP "pty\->set_utf8_mode (bool on)" 4
+.IX Item "pty->set_utf8_mode (bool on)"
+On systems supporting special \s-1UTF\-8\s0 line disciplines (e.g. Linux), this
+tries to enable this discipline for the given pty. Can be called at any
+time to change the mode.
+.SH "C INTERFACE: THE ptytty FAMILY OF FUNCTIONS"
+.IX Header "C INTERFACE: THE ptytty FAMILY OF FUNCTIONS"
+.IP "ptytty_init ()" 4
+.IX Item "ptytty_init ()"
+See \f(CW\*(C`ptytty::init ()\*(C'\fR.
+.IP "\s-1PTYTTY\s0 ptytty_create ()" 4
+.IX Item "PTYTTY ptytty_create ()"
+Creates a new opaque \s-1PTYTTY\s0 object and returns it. Do not try to access it
+in any way except by testing it for truthness (e.g. \f(CW\*(C`if (pty) ....\*(C'\fR). See
+\&\f(CW\*(C`ptytty::create ()\*(C'\fR.
+.IP "int ptytty_pty (\s-1PTYTTY\s0 ptytty)" 4
+.IX Item "int ptytty_pty (PTYTTY ptytty)"
+Return the pty file descriptor. See \f(CW\*(C`pty\->pty\*(C'\fR.
+.IP "int ptytty_tty (\s-1PTYTTY\s0 ptytty)" 4
+.IX Item "int ptytty_tty (PTYTTY ptytty)"
+Return the tty file descriptor. See \f(CW\*(C`pty\->tty\*(C'\fR.
+.IP "void ptytty_delete (\s-1PTYTTY\s0 ptytty)" 4
+.IX Item "void ptytty_delete (PTYTTY ptytty)"
+Destroys the \s-1PTYTTY\s0 object, freeing the pty/tty pair and cleaning up the
+utmp/wtmp/lastlog databases, if initialised/used. Same as \f(CW\*(C`delete pty\*(C'\fR in
+\&\*(C+.
+.IP "int ptytty_get (\s-1PTYTTY\s0 ptytty)" 4
+.IX Item "int ptytty_get (PTYTTY ptytty)"
+See \f(CW\*(C`pty\->get\*(C'\fR, returns 0 in case of an error, non-zero otherwise.
+.IP "void ptytty_login (\s-1PTYTTY\s0 ptytty, int cmd_pid, bool login_shell, const char *hostname)" 4
+.IX Item "void ptytty_login (PTYTTY ptytty, int cmd_pid, bool login_shell, const char *hostname)"
+See \f(CW\*(C`pty\->login\*(C'\fR.
+.IP "void ptytty_close_tty (\s-1PTYTTY\s0 ptytty)" 4
+.IX Item "void ptytty_close_tty (PTYTTY ptytty)"
+See \f(CW\*(C`pty\->close_tty\*(C'\fR.
+.IP "int ptytty_make_controlling_tty (\s-1PTYTTY\s0 ptytty)" 4
+.IX Item "int ptytty_make_controlling_tty (PTYTTY ptytty)"
+See \f(CW\*(C`pty\->make_controlling_tty\*(C'\fR.
+.IP "void ptytty_set_utf8_mode (\s-1PTYTTY\s0 ptytty, int on)" 4
+.IX Item "void ptytty_set_utf8_mode (PTYTTY ptytty, int on)"
+See \f(CW\*(C`pty\->set_utf8_mode\*(C'\fR.
+.IP "void ptytty_drop_privileges ()" 4
+.IX Item "void ptytty_drop_privileges ()"
+See \f(CW\*(C`ptytty::drop_privileges\*(C'\fR.
+.IP "void ptytty_use_helper ()" 4
+.IX Item "void ptytty_use_helper ()"
+See \f(CW\*(C`ptytty::use_helper\*(C'\fR.
+.SH "BUGS"
+.IX Header "BUGS"
+You kiddin'?
+.SH "AUTHORS"
+.IX Header "AUTHORS"
+Emanuele Giaquinta <e.giaquinta@glauco.it>, Marc Alexander Lehmann
+<rxvt\-unicode@schmorp.de>.
--- rxvt-unicode/libptytty/doc/libptytty.3.pod
+++ rxvt-unicode/libptytty/doc/libptytty.3.pod
@@ -0,0 +1,284 @@
+=head1 NAME
+
+libptytty - OS independent and secure pty/tty and utmp/wtmp/lastlog handling
+
+=head1 SYNOPSIS
+
+ cc ... -lptytty
+
+ #include <libptytty.h>
+
+
+ // C++
+ ptytty *pty = ptytty::create ();
+
+ if (!pty->get ())
+ // error allocating pty
+
+ if (we want utmp)
+ pty->login (process_pid, 0, "remote.host");
+ else if (we want utmp AND wtmp/lastlog)
+ pty->login (process_pid, 1, "remote.host");
+
+ // we are done with it
+ delete pty;
+
+
+ // C
+ PTYTTY pty = ptytty_create ();
+
+ if (!ptytty_get (pty))
+ // error allocating pty
+
+ if (we want utmp)
+ ptytty_login (pty, process_pid, 0, "remote.host");
+ else if (we want utmp AND wtmp/lastlog)
+ ptytty_login (pty, process_pid, 1, "remote.host");
+
+ // we are done with it
+ ptytty_delete (pty);
+
+See also the F<eg/> directory, which currently contains the F<c-sample.c>
+file that spawns a login shell from C using libptytty.
+
+=head1 DESCRIPTION
+
+Libptytty is a small library that offers pseudo-tty management in an
+OS-independent way. It was created out of frustration over the many
+differences of pty/tty handling in different operating systems for the use
+inside C<rxvt-unicode>.
+
+In addition to offering mere pty/tty management, it also offers session
+database support (utmp and optional wtmp/lastlog updates for login
+shells).
+
+It also supports fork'ing after startup and dropping privileges in the
+calling process, so in case the calling process gets compromised by the
+user starting the program there is less to gain, as only the helper
+process runs with privileges (e.g. setuid/setgid), which reduces the area
+of attack immensely.
+
+Libptytty is written in C++, but it also offers a C-only API.
+
+=head1 SECURITY CONSIDERATIONS
+
+I<< B<It is of paramount importance that you at least read the following
+paragraph!> >>
+
+If you write a typical terminal-like program that just wants one or more
+ptys, you should call the C<ptytty::init ()> method (C: C<ptytty_init ()>
+function) as the very first thing in your program:
+
+ int main (int argc, char *argv[])
+ {
+ // do nothing here
+ ptytty::init ();
+ // in C: ptytty_init ();
+
+ // initialise, parse arguments, etc.
+ }
+
+This checks whether the program runs setuid or setgid. If yes then it will
+fork a helper process and drop privileges.
+
+Some programs need finer control over if and when this helper process
+is started, and if and how to drop privileges. For those programs, the
+methods C<ptytty::use_helper> and C<ptytty::drop_privileges> (and possibly
+C<ptytty::sanitise_stdfd>) are more useful.
+
+=head1 C++ INTERFACE: THE ptytty CLASS
+
+=head2 STATIC METHODS
+
+=over 4
+
+=item ptytty::init ()
+
+The default way to initialise libptytty. Must be called immediately as
+the first thing in the C<main> function, or earlier e.g. during static
+construction time. The earlier, the better.
+
+This method calls C<sanitise_stdfd> and then checks whether the program runs
+with setuid/setgid permissions and, if yes, spawns a helper process for
+pty/tty management. It then drops the privileges completely, so the actual
+program runs without setuid/setgid privileges.
+
+On failure, this method terminates the process.
+
+=item ptytty::use_helper ()
+
+Tries to start a helper process that retains privileges even when the
+calling process does not. This is usually called from C<ptytty::init> when
+it detects that the program is running setuid or setgid, but can be called
+manually if it is inconvenient to drop privileges at startup, or when
+you are not running setuid/setgid but want to drop privileges (e.g. when
+running as a root-started daemon).
+
+This method will try not to start more than one helper process. The same
+helper process can usually be used both from the process starting it and
+all its fork'ed (not exec'ed) children.
+
+On failure, this method terminates the process.
+
+=item ptytty::drop_privileges ()
+
+Drops privileges completely, i.e. sets real, effective and saved user
+id to the real user id. Useful to make sure that the process doesn't
+run with special privileges.
+
+On failure, this method terminates the process.
+
+=item ptytty::sanitise_stdfd ()
+
+Checks whether file descriptors 0, 1 and 2 (stdin, stdout and stderr)
+are valid (open) and, if not, connects them to F</dev/tty> or
+F</dev/null> if possible. This is necessary because libptytty might
+want to output error messages to those descriptors, which at the time
+of outputting the error message, might be connected to something
+unsuitable opened by the unsuspecting program itself (this can be a
+security issue).
+
+On failure, this method terminates the process.
+
+=item bool success = ptytty::send_fd (int socket, int fd)
+
+Utility method to send a file descriptor over a unix domain
+socket. Returns true if successful, false otherwise. This method is only
+exposed for your convenience and is not required for normal operation.
+
+=item int fd = ptytty::recv_fd (int socket)
+
+Utility method to receive a file descriptor over a unix domain
+socket. Returns the fd if successful and C<-1> otherwise. This method
+is only exposed for your convenience and is not required for normal
+operation.
+
+=item ptytty *pty = ptytty::create ()
+
+Creates new ptytty object. Creation does not yet do anything besides
+allocating the structure.
+
+A static method is used because the actual ptytty implementation can
+differ at runtime, so you need a dynamic object creation facility.
+
+=back
+
+
+=head2 DYNAMIC/SESSION-RELATED DATA MEMBERS AND METHODS
+
+=over 4
+
+=item int pty_fd = pty->pty
+
+=item int tty_fd = pty->tty
+
+These members contain the pty and tty file descriptors, respectively. They
+initially contain C<-1> until a successful call to C<ptytty::get>.
+
+=item bool success = pty->get ()
+
+Tries to find, allocate and initialise a new pty/tty pair. Returns C<true>
+when successful.
+
+If the helper process is running and there is a protocol error, this
+method terminates the process.
+
+=item pty->login (int cmd_pid, bool login_shell, const char *hostname)
+
+Creates an entry in the systems session database(s) (utmp, wtmp, lastlog).
+C<cmd_pid> must be the pid of the process representing the session
+(such as the login shell), C<login_shell> defines whether the session is
+associated with a login, which influences whether wtmp and lastlog entries
+are created, and C<hostname> should identify the "hostname" the user logs
+in from, which often is the value of the C<DISPLAY> variable or tty line
+in case of local logins.
+
+Calling this method is optional. A session starts at the time of the login
+call and extends until the ptytty object is destroyed.
+
+=item pty->close_tty ()
+
+Closes the tty. Useful after forking in the parent/pty process.
+
+=item bool success = pty->make_controlling_tty ()
+
+Tries to make the pty/tty pair the controlling terminal of the current
+process. Useful after forking in the child/tty process.
+
+=item pty->set_utf8_mode (bool on)
+
+On systems supporting special UTF-8 line disciplines (e.g. Linux), this
+tries to enable this discipline for the given pty. Can be called at any
+time to change the mode.
+
+=back
+
+
+=head1 C INTERFACE: THE ptytty FAMILY OF FUNCTIONS
+
+=over 4
+
+=item ptytty_init ()
+
+See C<ptytty::init ()>.
+
+=item PTYTTY ptytty_create ()
+
+Creates a new opaque PTYTTY object and returns it. Do not try to access it
+in any way except by testing it for truthness (e.g. C<if (pty) ....>). See
+C<ptytty::create ()>.
+
+=item int ptytty_pty (PTYTTY ptytty)
+
+Return the pty file descriptor. See C<< pty->pty >>.
+
+=item int ptytty_tty (PTYTTY ptytty)
+
+Return the tty file descriptor. See C<< pty->tty >>.
+
+=item void ptytty_delete (PTYTTY ptytty)
+
+Destroys the PTYTTY object, freeing the pty/tty pair and cleaning up the
+utmp/wtmp/lastlog databases, if initialised/used. Same as C<delete pty> in
+C++.
+
+=item int ptytty_get (PTYTTY ptytty)
+
+See C<< pty->get >>, returns 0 in case of an error, non-zero otherwise.
+
+=item void ptytty_login (PTYTTY ptytty, int cmd_pid, bool login_shell, const char *hostname)
+
+See C<< pty->login >>.
+
+=item void ptytty_close_tty (PTYTTY ptytty)
+
+See C<< pty->close_tty >>.
+
+=item int ptytty_make_controlling_tty (PTYTTY ptytty)
+
+See C<< pty->make_controlling_tty >>.
+
+=item void ptytty_set_utf8_mode (PTYTTY ptytty, int on)
+
+See C<< pty->set_utf8_mode >>.
+
+=item void ptytty_drop_privileges ()
+
+See C<< ptytty::drop_privileges >>.
+
+=item void ptytty_use_helper ()
+
+See C<< ptytty::use_helper >>.
+
+=back
+
+
+=head1 BUGS
+
+You kiddin'?
+
+=head1 AUTHORS
+
+Emanuele Giaquinta <e.giaquinta@glauco.it>, Marc Alexander Lehmann
+<rxvt-unicode@schmorp.de>.
+
--- rxvt-unicode/libptytty/eg/c-sample.c
+++ rxvt-unicode/libptytty/eg/c-sample.c
@@ -0,0 +1,73 @@
+// on my system, this program outputs:
+//
+// who; echo 'Hello, World!'; exit
+// # root pts/9 Jan 25 12:12 (libptytty.example.net)
+// Hello, World!
+//
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <libptytty.h>
+
+int main (void)
+{
+ ptytty_init ();
+
+ PTYTTY pty = ptytty_create ();
+
+ if (!ptytty_get (pty))
+ printf ("unable to open pty\n"), exit (EXIT_FAILURE);
+
+ pid_t pid = fork ();
+
+ if (pid < 0)
+ printf ("fork error\n"), exit (EXIT_FAILURE);
+
+ int pty_fd = ptytty_pty (pty);
+ int tty_fd = ptytty_tty (pty);
+
+ if (pid)
+ {
+ ptytty_close_tty (pty);
+ ptytty_login (pty, pid, 1, "libptytty.example.net");
+
+ char s[] = "who; echo 'Hello, World!'; exit\015";
+
+ write (pty_fd, s, sizeof (s) - 1);
+
+ char buf[1024];
+
+ for (;;)
+ {
+ int len = read (pty_fd, buf, 1024);
+
+ if (len <= 0)
+ break;
+
+ write (STDOUT_FILENO, buf, len);
+ }
+
+ ptytty_delete (pty);
+ }
+ else
+ {
+ ptytty_make_controlling_tty (pty);
+
+ close (pty_fd);
+ dup2 (tty_fd, STDIN_FILENO );
+ dup2 (tty_fd, STDOUT_FILENO);
+ dup2 (tty_fd, STDERR_FILENO);
+ close (tty_fd);
+
+ execl ("/bin/sh", "-sh", (char *)0);
+ _exit (EXIT_FAILURE);
+ }
+
+ return EXIT_SUCCESS;
+}
+
+
--- rxvt-unicode/libptytty/Makefile.am
+++ rxvt-unicode/libptytty/Makefile.am
@@ -0,0 +1,27 @@
+AUTOMAKE_OPTIONS = foreign subdir-objects
+ACLOCAL_AMFLAGS = -I .
+
+EXTRA_DIST = Changes README doc/libptytty.3.pod doc/libptytty.3 eg/c-sample.c \
+ src/ptytty.h src/ptytty_conf.h src/estl.h src/ecb.h
+
+man_MANS = doc/libptytty.3
+
+include_HEADERS = src/libptytty.h
+
+lib_LTLIBRARIES = libptytty.la
+
+libptytty_la_SOURCES = src/c-api.C src/fdpass.C src/logging.C src/proxy.C src/ptytty.C
+
+noinst_PROGRAMS = c-sample
+c_sample_SOURCES = eg/c-sample.c
+c_sample_LDADD = libptytty.la
+c_sample_CPPFLAGS = -I$(top_srcdir)/src
+c_sample_LINK = $(CXXLINK)
+
+$(srcdir)/doc/libptytty.3: $(srcdir)/doc/libptytty.3.pod
+ pod2man -n libptytty -r "$(VERSION)" -q\" -c LIBPTYTTY -s3 <$< >$@
+
+$(srcdir)/README: $(srcdir)/doc/libptytty.3.pod
+ pod2text <$< >$@
+
+alldoc: $(srcdir)/doc/libptytty.3 $(srcdir)/README
--- rxvt-unicode/libptytty/README
+++ rxvt-unicode/libptytty/README
@@ -0,0 +1,239 @@
+NAME
+ libptytty - OS independent and secure pty/tty and utmp/wtmp/lastlog
+ handling
+
+SYNOPSIS
+ cc ... -lptytty
+
+ #include <libptytty.h>
+
+
+ // C++
+ ptytty *pty = ptytty::create ();
+
+ if (!pty->get ())
+ // error allocating pty
+
+ if (we want utmp)
+ pty->login (process_pid, 0, "remote.host");
+ else if (we want utmp AND wtmp/lastlog)
+ pty->login (process_pid, 1, "remote.host");
+
+ // we are done with it
+ delete pty;
+
+
+ // C
+ PTYTTY pty = ptytty_create ();
+
+ if (!ptytty_get (pty))
+ // error allocating pty
+
+ if (we want utmp)
+ ptytty_login (pty, process_pid, 0, "remote.host");
+ else if (we want utmp AND wtmp/lastlog)
+ ptytty_login (pty, process_pid, 1, "remote.host");
+
+ // we are done with it
+ ptytty_delete (pty);
+
+ See also the eg/ directory, which currently contains the c-sample.c file
+ that spawns a login shell from C using libptytty.
+
+DESCRIPTION
+ Libptytty is a small library that offers pseudo-tty management in an
+ OS-independent way. It was created out of frustration over the many
+ differences of pty/tty handling in different operating systems for the
+ use inside "rxvt-unicode".
+
+ In addition to offering mere pty/tty management, it also offers session
+ database support (utmp and optional wtmp/lastlog updates for login
+ shells).
+
+ It also supports fork'ing after startup and dropping privileges in the
+ calling process, so in case the calling process gets compromised by the
+ user starting the program there is less to gain, as only the helper
+ process runs with privileges (e.g. setuid/setgid), which reduces the
+ area of attack immensely.
+
+ Libptytty is written in C++, but it also offers a C-only API.
+
+SECURITY CONSIDERATIONS
+ *It is of paramount importance that you at least read the following
+ paragraph!*
+
+ If you write a typical terminal-like program that just wants one or more
+ ptys, you should call the "ptytty::init ()" method (C: "ptytty_init ()"
+ function) as the very first thing in your program:
+
+ int main (int argc, char *argv[])
+ {
+ // do nothing here
+ ptytty::init ();
+ // in C: ptytty_init ();
+
+ // initialise, parse arguments, etc.
+ }
+
+ This checks whether the program runs setuid or setgid. If yes then it
+ will fork a helper process and drop privileges.
+
+ Some programs need finer control over if and when this helper process is
+ started, and if and how to drop privileges. For those programs, the
+ methods "ptytty::use_helper" and "ptytty::drop_privileges" (and possibly
+ "ptytty::sanitise_stdfd") are more useful.
+
+C++ INTERFACE: THE ptytty CLASS
+ STATIC METHODS
+ ptytty::init ()
+ The default way to initialise libptytty. Must be called immediately
+ as the first thing in the "main" function, or earlier e.g. during
+ static construction time. The earlier, the better.
+
+ This method calls "sanitise_stdfd" and then checks whether the
+ program runs with setuid/setgid permissions and, if yes, spawns a
+ helper process for pty/tty management. It then drops the privileges
+ completely, so the actual program runs without setuid/setgid
+ privileges.
+
+ On failure, this method terminates the process.
+
+ ptytty::use_helper ()
+ Tries to start a helper process that retains privileges even when
+ the calling process does not. This is usually called from
+ "ptytty::init" when it detects that the program is running setuid or
+ setgid, but can be called manually if it is inconvenient to drop
+ privileges at startup, or when you are not running setuid/setgid but
+ want to drop privileges (e.g. when running as a root-started
+ daemon).
+
+ This method will try not to start more than one helper process. The
+ same helper process can usually be used both from the process
+ starting it and all its fork'ed (not exec'ed) children.
+
+ On failure, this method terminates the process.
+
+ ptytty::drop_privileges ()
+ Drops privileges completely, i.e. sets real, effective and saved
+ user id to the real user id. Useful to make sure that the process
+ doesn't run with special privileges.
+
+ On failure, this method terminates the process.
+
+ ptytty::sanitise_stdfd ()
+ Checks whether file descriptors 0, 1 and 2 (stdin, stdout and
+ stderr) are valid (open) and, if not, connects them to /dev/tty or
+ /dev/null if possible. This is necessary because libptytty might
+ want to output error messages to those descriptors, which at the
+ time of outputting the error message, might be connected to
+ something unsuitable opened by the unsuspecting program itself (this
+ can be a security issue).
+
+ On failure, this method terminates the process.
+
+ bool success = ptytty::send_fd (int socket, int fd)
+ Utility method to send a file descriptor over a unix domain socket.
+ Returns true if successful, false otherwise. This method is only
+ exposed for your convenience and is not required for normal
+ operation.
+
+ int fd = ptytty::recv_fd (int socket)
+ Utility method to receive a file descriptor over a unix domain
+ socket. Returns the fd if successful and -1 otherwise. This method
+ is only exposed for your convenience and is not required for normal
+ operation.
+
+ ptytty *pty = ptytty::create ()
+ Creates new ptytty object. Creation does not yet do anything besides
+ allocating the structure.
+
+ A static method is used because the actual ptytty implementation can
+ differ at runtime, so you need a dynamic object creation facility.
+
+ DYNAMIC/SESSION-RELATED DATA MEMBERS AND METHODS
+ int pty_fd = pty->pty
+ int tty_fd = pty->tty
+ These members contain the pty and tty file descriptors,
+ respectively. They initially contain -1 until a successful call to
+ "ptytty::get".
+
+ bool success = pty->get ()
+ Tries to find, allocate and initialise a new pty/tty pair. Returns
+ "true" when successful.
+
+ If the helper process is running and there is a protocol error, this
+ method terminates the process.
+
+ pty->login (int cmd_pid, bool login_shell, const char *hostname)
+ Creates an entry in the systems session database(s) (utmp, wtmp,
+ lastlog). "cmd_pid" must be the pid of the process representing the
+ session (such as the login shell), "login_shell" defines whether the
+ session is associated with a login, which influences whether wtmp
+ and lastlog entries are created, and "hostname" should identify the
+ "hostname" the user logs in from, which often is the value of the
+ "DISPLAY" variable or tty line in case of local logins.
+
+ Calling this method is optional. A session starts at the time of the
+ login call and extends until the ptytty object is destroyed.
+
+ pty->close_tty ()
+ Closes the tty. Useful after forking in the parent/pty process.
+
+ bool success = pty->make_controlling_tty ()
+ Tries to make the pty/tty pair the controlling terminal of the
+ current process. Useful after forking in the child/tty process.
+
+ pty->set_utf8_mode (bool on)
+ On systems supporting special UTF-8 line disciplines (e.g. Linux),
+ this tries to enable this discipline for the given pty. Can be
+ called at any time to change the mode.
+
+C INTERFACE: THE ptytty FAMILY OF FUNCTIONS
+ ptytty_init ()
+ See "ptytty::init ()".
+
+ PTYTTY ptytty_create ()
+ Creates a new opaque PTYTTY object and returns it. Do not try to
+ access it in any way except by testing it for truthness (e.g. "if
+ (pty) ...."). See "ptytty::create ()".
+
+ int ptytty_pty (PTYTTY ptytty)
+ Return the pty file descriptor. See "pty->pty".
+
+ int ptytty_tty (PTYTTY ptytty)
+ Return the tty file descriptor. See "pty->tty".
+
+ void ptytty_delete (PTYTTY ptytty)
+ Destroys the PTYTTY object, freeing the pty/tty pair and cleaning up
+ the utmp/wtmp/lastlog databases, if initialised/used. Same as
+ "delete pty" in C++.
+
+ int ptytty_get (PTYTTY ptytty)
+ See "pty->get", returns 0 in case of an error, non-zero otherwise.
+
+ void ptytty_login (PTYTTY ptytty, int cmd_pid, bool login_shell, const
+ char *hostname)
+ See "pty->login".
+
+ void ptytty_close_tty (PTYTTY ptytty)
+ See "pty->close_tty".
+
+ int ptytty_make_controlling_tty (PTYTTY ptytty)
+ See "pty->make_controlling_tty".
+
+ void ptytty_set_utf8_mode (PTYTTY ptytty, int on)
+ See "pty->set_utf8_mode".
+
+ void ptytty_drop_privileges ()
+ See "ptytty::drop_privileges".
+
+ void ptytty_use_helper ()
+ See "ptytty::use_helper".
+
+BUGS
+ You kiddin'?
+
+AUTHORS
+ Emanuele Giaquinta <e.giaquinta@glauco.it>, Marc Alexander Lehmann
+ <rxvt-unicode@schmorp.de>.
+
--- rxvt-unicode/libptytty/src/c-api.C
+++ rxvt-unicode/libptytty/src/c-api.C
@@ -0,0 +1,66 @@
+/*----------------------------------------------------------------------*
+ * File: c-api.C
+ *----------------------------------------------------------------------*
+ *
+ * All portions of code are copyright by their respective author/s.
+ * Copyright (c) 2005 Marc Lehmann <pcg@goof.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *---------------------------------------------------------------------*/
+
+#include "config.h"
+
+#include "ptytty.h"
+
+/////////////////////////////////////////////////////////////////////////////
+// C API
+
+#ifndef PTYTTY_NO_C_API
+
+typedef void *PTYTTY;
+
+#define DEFINE_METHOD(retval, name, args1, args2) \
+extern "C" retval ptytty_ ## name args1 \
+{ return ((struct ptytty *)ptytty)->name args2; }
+
+DEFINE_METHOD(int,pty,(PTYTTY ptytty),)
+DEFINE_METHOD(int,tty,(PTYTTY ptytty),)
+DEFINE_METHOD(int,get,(PTYTTY ptytty),())
+DEFINE_METHOD(void,login,(PTYTTY ptytty, int cmd_pid, int login_shell, const char *hostname),(cmd_pid,login_shell,hostname))
+
+DEFINE_METHOD(void,close_tty,(PTYTTY ptytty),())
+DEFINE_METHOD(int,make_controlling_tty,(PTYTTY ptytty),())
+DEFINE_METHOD(void,set_utf8_mode,(PTYTTY ptytty, int on),(on))
+
+#define DEFINE_STATIC(retval, name, args) \
+extern "C" retval ptytty_ ## name args \
+{ return ptytty::name args; }
+
+DEFINE_STATIC(void,drop_privileges,())
+DEFINE_STATIC(void,use_helper,())
+DEFINE_STATIC(void,sanitise_stdfd,())
+DEFINE_STATIC(void,init,())
+
+DEFINE_STATIC(PTYTTY,create,())
+
+extern "C" void ptytty_delete (PTYTTY ptytty)
+{
+ delete (struct ptytty *)ptytty;
+}
+
+// send_fd, recv_fd not exposed
+
+#endif
+
--- rxvt-unicode/MANIFEST
+++ rxvt-unicode/MANIFEST
@@ -42,7 +42,6 @@
src/.cvsignore
src/Makefile.in
-src/background.C
src/callback.h
src/command.C
src/command.h
--- rxvt-unicode/src/background.C
+++ rxvt-unicode/src/background.C
@@ -1,544 +0,0 @@
-/*----------------------------------------------------------------------*
- * File: background.C
- *----------------------------------------------------------------------*
- *
- * All portions of code are copyright by their respective author/s.
- * Copyright (c) 2005-2008 Marc Lehmann <schmorp@schmorp.de>
- * Copyright (c) 2007 Sasha Vasko <sasha@aftercode.net>
- * Copyright (c) 2010-2012 Emanuele Giaquinta <e.giaquinta@glauco.it>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *---------------------------------------------------------------------*/
-
-#include "../config.h" /* NECESSARY */
-#include "rxvt.h" /* NECESSARY */
-
-#ifdef HAVE_BG_PIXMAP
-
-void
-rxvt_term::bg_destroy ()
-{
-# if BG_IMAGE_FROM_ROOT
- delete root_img;
- root_img = 0;
-# endif
-
-# if BG_IMAGE_FROM_FILE
- fimage.destroy ();
-# endif
-}
-
-bool
-rxvt_term::bg_window_size_sensitive ()
-{
-# if BG_IMAGE_FROM_ROOT
- if (root_img)
- return true;
-# endif
-
-# if BG_IMAGE_FROM_FILE
- if (fimage.img)
- {
- if ((fimage.flags & IM_IS_SIZE_SENSITIVE)
- || fimage.img->w > szHint.width
- || fimage.img->h > szHint.height)
- return true;
- }
-# endif
-
- return false;
-}
-
-bool
-rxvt_term::bg_window_position_sensitive ()
-{
-# if BG_IMAGE_FROM_ROOT
- if (root_img)
- return true;
-# endif
-
-# if BG_IMAGE_FROM_FILE
- if (fimage.img)
- {
- if (fimage.flags & IM_ROOT_ALIGN)
- return true;
- }
-# endif
-
- return false;
-}
-
-# if BG_IMAGE_FROM_FILE
-static inline int
-make_align_position (int align, int window_size, int image_size)
-{
- if (align >= 0 && align <= 100)
- return lerp (0, window_size - image_size, align);
- else if (align > 100)
- return lerp (window_size - image_size, window_size, align - 100);
- else
- return lerp (-image_size, 0, align + 100);
-}
-
-static void
-parse_style (const char *style, int &x, int &y, unsigned int &w, unsigned int &h, uint8_t &flags)
-{
- if (!strcasecmp (style, "tiled"))
- {
- flags = IM_TILE;
- w = h = noScale;
- x = y = 0;
- }
- else if (!strcasecmp (style, "aspect-stretched"))
- {
- flags = IM_KEEP_ASPECT;
- w = h = windowScale;
- x = y = centerAlign;
- }
- else if (!strcasecmp (style, "stretched"))
- {
- flags = 0;
- w = h = windowScale;
- x = y = centerAlign;
- }
- else if (!strcasecmp (style, "centered"))
- {
- flags = 0;
- w = h = noScale;
- x = y = centerAlign;
- }
- else if (!strcasecmp (style, "root-tiled"))
- {
- flags = IM_TILE|IM_ROOT_ALIGN;
- w = h = noScale;
- x = y = 0;
- }
-}
-
-bool
-rxvt_image::set_geometry (const char *geom, bool update)
-{
- bool changed = false;
- int geom_flags = 0;
- int x = h_align;
- int y = v_align;
- unsigned int w = h_scale;
- unsigned int h = v_scale;
- uint8_t new_flags = 0;
-
- if (geom == NULL)
- return false;
-
- if (geom[0])
- {
- char **arr = rxvt_strsplit (':', geom);
-
- for (int i = 0; arr[i]; i++)
- {
- if (!strncasecmp (arr[i], "style=", 6))
- {
- parse_style (arr[i] + 6, x, y, w, h, new_flags);
- geom_flags = WidthValue|HeightValue|XValue|YValue;
- }
- else if (!strcasecmp (arr[i], "op=tile"))
- new_flags |= IM_TILE;
- else if (!strcasecmp (arr[i], "op=keep-aspect"))
- new_flags |= IM_KEEP_ASPECT;
- else if (!strcasecmp (arr[i], "op=root-align"))
- new_flags |= IM_ROOT_ALIGN;
-
- // deprecated
- else if (!strcasecmp (arr[i], "tile"))
- {
- new_flags |= IM_TILE;
- w = h = noScale;
- geom_flags |= WidthValue|HeightValue;
- }
- else if (!strcasecmp (arr[i], "propscale"))
- {
- new_flags |= IM_KEEP_ASPECT;
- w = h = windowScale;
- geom_flags |= WidthValue|HeightValue;
- }
- else if (!strcasecmp (arr[i], "hscale"))
- {
- new_flags |= IM_TILE;
- w = windowScale;
- h = noScale;
- geom_flags |= WidthValue|HeightValue;
- }
- else if (!strcasecmp (arr[i], "vscale"))
- {
- new_flags |= IM_TILE;
- h = windowScale;
- w = noScale;
- geom_flags |= WidthValue|HeightValue;
- }
- else if (!strcasecmp (arr[i], "scale"))
- {
- w = h = windowScale;
- geom_flags |= WidthValue|HeightValue;
- }
- else if (!strcasecmp (arr[i], "auto"))
- {
- w = h = windowScale;
- x = y = centerAlign;
- geom_flags |= WidthValue|HeightValue|XValue|YValue;
- }
- else if (!strcasecmp (arr[i], "root"))
- {
- new_flags |= IM_TILE|IM_ROOT_ALIGN;
- w = h = noScale;
- geom_flags |= WidthValue|HeightValue;
- }
-
- else
- geom_flags |= XParseGeometry (arr[i], &x, &y, &w, &h);
- } /* done parsing ops */
-
- rxvt_free_strsplit (arr);
- }
-
- new_flags |= flags & ~IM_GEOMETRY_FLAGS;
-
- if (!update)
- {
- if (!(geom_flags & XValue))
- x = y = defaultAlign;
- else if (!(geom_flags & YValue))
- y = x;
-
- if (!(geom_flags & (WidthValue|HeightValue)))
- w = h = defaultScale;
- else if (!(geom_flags & HeightValue))
- h = w;
- else if (!(geom_flags & WidthValue))
- w = h;
- }
-
- clamp_it (x, -100, 200);
- clamp_it (y, -100, 200);
-
- if (flags != new_flags
- || h_scale != w
- || v_scale != h
- || h_align != x
- || v_align != y)
- {
- flags = new_flags;
- h_scale = w;
- v_scale = h;
- h_align = x;
- v_align = y;
- changed = true;
- }
-
- if (is_size_sensitive ())
- flags |= IM_IS_SIZE_SENSITIVE;
- else
- flags &= ~IM_IS_SIZE_SENSITIVE;
-
- return changed;
-}
-
-void
-rxvt_term::render_image (rxvt_image &image)
-{
- int image_width = image.img->w;
- int image_height = image.img->h;
- int parent_width = szHint.width;
- int parent_height = szHint.height;
- int h_scale = min (image.h_scale, 32767 * 100 / parent_width);
- int v_scale = min (image.v_scale, 32767 * 100 / parent_height);
-
- int w;
- int h;
- int x;
- int y;
-
- w = h_scale * parent_width / 100;
- h = v_scale * parent_height / 100;
-
- if (image.flags & IM_KEEP_ASPECT)
- {
- float scale = (float)w / image_width;
- min_it (scale, (float)h / image_height);
- w = image_width * scale + 0.5;
- h = image_height * scale + 0.5;
- }
-
- if (!w) w = image_width;
- if (!h) h = image_height;
-
- if (image.flags & IM_ROOT_ALIGN)
- {
- x = -parent_x;
- y = -parent_y;
- }
- else
- {
- x = make_align_position (image.h_align, parent_width, w);
- y = make_align_position (image.v_align, parent_height, h);
- }
-
- if (!(image.flags & IM_ROOT_ALIGN)
- && (x >= parent_width
- || y >= parent_height
- || x + w <= 0
- || y + h <= 0))
- return;
-
- rxvt_img *img = image.img->scale (w, h);
-
- if (image.flags & IM_TILE)
- img->repeat_mode (RepeatNormal);
- else
- img->repeat_mode (RepeatNone);
- img->sub_rect (-x, -y, parent_width, parent_height)->replace (img);
-
- if (bg_img)
- img->draw (bg_img, PictOpOver, image.alpha * 1. / 0xffff);
-
- XRenderPictFormat *format = XRenderFindVisualFormat (dpy, visual);
- img->convert_format (format, pix_colors [Color_bg])->replace (img);
-
- delete bg_img;
- bg_img = img;
-}
-
-rxvt_image::rxvt_image ()
-{
- alpha = 0xffff;
- flags = 0;
- h_scale =
- v_scale = defaultScale;
- h_align =
- v_align = defaultAlign;
-
- img = 0;
-}
-
-void
-rxvt_image::set_file_geometry (rxvt_screen *s, const char *file)
-{
- if (!file || !*file)
- return;
-
- const char *p = strchr (file, ';');
-
- if (p)
- {
- size_t len = p - file;
- char *f = rxvt_temp_buf<char> (len + 1);
- memcpy (f, file, len);
- f[len] = '\0';
- file = f;
- }
-
- set_file (s, file);
- alpha = 0x8000;
- set_geometry (p ? p + 1 : "");
-}
-
-void
-rxvt_image::set_file (rxvt_screen *s, const char *file)
-{
- rxvt_img *img2 = rxvt_img::new_from_file (s, file);
- delete img;
- img = img2;
-}
-
-# endif /* BG_IMAGE_FROM_FILE */
-
-bool
-image_effects::set_blur (const char *geom)
-{
- bool changed = false;
- unsigned int hr, vr;
- int junk;
- int geom_flags = XParseGeometry (geom, &junk, &junk, &hr, &vr);
-
- if (!(geom_flags & WidthValue))
- hr = 1;
- if (!(geom_flags & HeightValue))
- vr = hr;
-
- min_it (hr, 128);
- min_it (vr, 128);
-
- if (h_blurRadius != hr)
- {
- changed = true;
- h_blurRadius = hr;
- }
-
- if (v_blurRadius != vr)
- {
- changed = true;
- v_blurRadius = vr;
- }
-
- return changed;
-}
-
-bool
-image_effects::set_tint (const rxvt_color &new_tint)
-{
- if (!tint_set || tint != new_tint)
- {
- tint = new_tint;
- tint_set = true;
-
- return true;
- }
-
- return false;
-}
-
-bool
-image_effects::set_shade (const char *shade_str)
-{
- int new_shade = atoi (shade_str);
-
- clamp_it (new_shade, -100, 200);
- if (new_shade < 0)
- new_shade = 200 - (100 + new_shade);
-
- if (new_shade != shade)
- {
- shade = new_shade;
- return true;
- }
-
- return false;
-}
-
-# if BG_IMAGE_FROM_ROOT
-/*
- * Builds a pixmap of the same size as the terminal window that contains
- * the tiled portion of the root pixmap that is supposed to be covered by
- * our window.
- */
-void
-rxvt_term::render_root_image ()
-{
- /* root dimensions may change from call to call - but Display structure should
- * be always up-to-date, so let's use it :
- */
- int screen = display->screen;
- int root_width = DisplayWidth (dpy, screen);
- int root_height = DisplayHeight (dpy, screen);
- int parent_width = szHint.width;
- int parent_height = szHint.height;
- int sx, sy;
-
- sx = parent_x;
- sy = parent_y;
-
- /* check if we are outside of the visible part of the virtual screen : */
- if (sx + parent_width <= 0 || sy + parent_height <= 0
- || sx >= root_width || sy >= root_height)
- return;
-
- while (sx < 0) sx += root_img->w;
- while (sy < 0) sy += root_img->h;
-
- rxvt_img *img = root_img->sub_rect (sx, sy, parent_width, parent_height);
-
- if (root_effects.need_blur ())
- img->blur (root_effects.h_blurRadius, root_effects.v_blurRadius)->replace (img);
-
- if (root_effects.need_tint ())
- {
- rgba c (rgba::MAX_CC, rgba::MAX_CC, rgba::MAX_CC);
-
- if (root_effects.tint_set)
- root_effects.tint.get (c);
- rxvt_img::nv factor = root_effects.shade / 100. - 1.;
- img->shade (factor, c)->replace (img);
- }
-
- XRenderPictFormat *format = XRenderFindVisualFormat (dpy, visual);
- img->convert_format (format, pix_colors [Color_bg])->replace (img);
-
- delete bg_img;
- bg_img = img;
-}
-# endif /* BG_IMAGE_FROM_ROOT */
-
-void
-rxvt_term::bg_render ()
-{
- if (bg_flags & BG_INHIBIT_RENDER)
- return;
-
- delete bg_img;
- bg_img = 0;
- bg_flags = 0;
-
- if (!mapped)
- return;
-
-# if BG_IMAGE_FROM_ROOT
- if (root_img)
- {
- render_root_image ();
- bg_flags |= BG_IS_TRANSPARENT;
- }
-# endif
-
-# if BG_IMAGE_FROM_FILE
- if (fimage.img)
- render_image (fimage);
-# endif
-
- scr_recolor (false);
- bg_flags |= BG_NEEDS_REFRESH;
-
- bg_valid_since = ev::now ();
-}
-
-void
-rxvt_term::bg_init ()
-{
-#if BG_IMAGE_FROM_ROOT
- if (option (Opt_transparent))
- {
- if (rs [Rs_blurradius])
- root_effects.set_blur (rs [Rs_blurradius]);
-
- if (ISSET_PIXCOLOR (Color_tint))
- root_effects.set_tint (pix_colors_focused [Color_tint]);
-
- if (rs [Rs_shade])
- root_effects.set_shade (rs [Rs_shade]);
-
- rxvt_img::new_from_root (this)->replace (root_img);
- XSelectInput (dpy, display->root, PropertyChangeMask);
- rootwin_ev.start (display, display->root);
- }
-#endif
-
-#if BG_IMAGE_FROM_FILE
- if (rs[Rs_backgroundPixmap])
- {
- fimage.set_file_geometry (this, rs[Rs_backgroundPixmap]);
- if (!bg_window_position_sensitive ())
- update_background ();
- }
-#endif
-}
-
-#endif /* HAVE_BG_PIXMAP */
--- rxvt-unicode/src/command.C
+++ rxvt-unicode/src/command.C
@@ -1484,16 +1484,6 @@
bool want_position_change = SHOULD_INVOKE (HOOK_POSITION_CHANGE);
- bool moved = false;
-#ifdef HAVE_BG_PIXMAP
- if (bg_window_position_sensitive ())
- {
- want_position_change = true;
- if (bg_img == 0)
- moved = true;
- }
-#endif
-
if (want_position_change)
{
int x, y;
@@ -1511,7 +1501,6 @@
parent_x = x;
parent_y = y;
HOOK_INVOKE ((this, HOOK_POSITION_CHANGE, DT_INT, x, DT_INT, y, DT_END));
- moved = true;
}
}
@@ -1520,13 +1509,6 @@
seen_resize = 1;
resize_all_windows (ev.xconfigure.width, ev.xconfigure.height, 1);
}
- else
- {
-#ifdef HAVE_BG_PIXMAP
- if (moved)
- update_background ();
-#endif
- }
HOOK_INVOKE ((this, HOOK_CONFIGURE_NOTIFY, DT_XEVENT, &ev, DT_END));
}
@@ -1545,17 +1527,6 @@
break;
case MapNotify:
-#ifdef HAVE_BG_PIXMAP
- // This is needed at startup for the case of no window manager
- // or a non-reparenting window manager and also because we
- // defer bg image updates if the window is not mapped. The
- // short delay is to optimize for multiple ConfigureNotify
- // events at startup when the window manager reparents the
- // window, so as to perform the computation after we have
- // received all of them.
- if (bg_img == 0)
- update_background_ev.start (0.025);
-#endif
mapped = 1;
#ifdef TEXT_BLINK
text_blink_ev.start ();
@@ -1789,6 +1760,9 @@
#if ENABLE_FRILLS
if (option (Opt_urgentOnBell))
set_urgency (0);
+
+ if (priv_modes & PrivMode_FocusEvent)
+ tt_printf ("\x1b[I");
#endif
HOOK_INVOKE ((this, HOOK_FOCUS_IN, DT_END));
@@ -1806,6 +1780,9 @@
#if ENABLE_FRILLS
if (option (Opt_urgentOnBell))
set_urgency (0);
+
+ if (priv_modes & PrivMode_FocusEvent)
+ tt_printf ("\x1b[O");
#endif
#if ENABLE_FRILLS || ISO_14755
if (iso14755buf)
@@ -1854,7 +1831,7 @@
#endif
}
-#if BG_IMAGE_FROM_ROOT || ENABLE_PERL
+#if ENABLE_PERL
void ecb_hot
rxvt_term::rootwin_cb (XEvent &ev)
{
@@ -1874,13 +1851,6 @@
if (ev.xproperty.atom == xa[XA_XROOTPMAP_ID]
|| ev.xproperty.atom == xa[XA_ESETROOT_PMAP_ID])
{
-#if BG_IMAGE_FROM_ROOT
- if (option (Opt_transparent))
- {
- rxvt_img::new_from_root (this)->replace (root_img);
- update_background ();
- }
-#endif
HOOK_INVOKE ((this, HOOK_ROOTPMAP_CHANGE, DT_END));
}
@@ -2725,7 +2695,7 @@
/* kidnapped escape sequence: Should be 8.3.48 */
case C1_ESA: /* ESC G */
// used by original rxvt for rob nations own graphics mode
- if (cmd_getc () == 'Q')
+ if (cmd_getc () == 'Q' && option (Opt_insecure))
tt_printf ("\033G0\012"); /* query graphics - no graphics */
break;
@@ -2944,7 +2914,7 @@
break;
case CSI_CUB: /* 8.3.18: (1) CURSOR LEFT */
- case CSI_HPB: /* 8.3.59: (1) CHARACTER POSITION BACKWARD */
+ case CSI_HPB: /* 8.3.59: (1) CHARACTER POSITION BACKWARD */
#ifdef ISO6429
arg[0] = -arg[0];
#else /* emulate common DEC VTs */
@@ -3330,6 +3300,94 @@
}
}
+static unsigned int
+colorcube_index (unsigned int idx_r,
+ unsigned int idx_g,
+ unsigned int idx_b)
+{
+ assert (idx_r < Red_levels);
+ assert (idx_g < Green_levels);
+ assert (idx_b < Blue_levels);
+
+ return idx_r * Blue_levels * Green_levels +
+ idx_g * Blue_levels +
+ idx_b;
+}
+
+/*
+ * Find the nearest color slot in the hidden color cube,
+ * adapt its value to the 32bit RGBA color.
+ */
+unsigned int
+rxvt_term::map_rgb24_color (unsigned int r, unsigned int g, unsigned int b, unsigned int a)
+{
+ r &= 0xff;
+ g &= 0xff;
+ b &= 0xff;
+ a &= 0xff;
+
+ uint32_t color = (a << 24) | (r << 16) | (g << 8) | b;
+
+ unsigned int idx_r = r * (Red_levels - 1) / 0xff;
+ unsigned int idx_g = g * (Green_levels - 1) / 0xff;
+ unsigned int idx_b = b * (Blue_levels - 1) / 0xff;
+ unsigned int idx = colorcube_index (idx_r, idx_g, idx_b);
+
+ /* we allow one of the 6 directly neighbouring colours */
+ /* to replace the current color, if they not used recently */
+ static const signed char dxyz[][3] = {
+ 0, 0, 0,
+ 0, 0, +1,
+ 0, 0, -1,
+ 0, +1, 0,
+ 0, -1, 0,
+ +1, 0, 0,
+ -1, 0, 0,
+ };
+
+ for (int n = 0; n < ecb_array_length (dxyz); ++n)
+ {
+ int r = idx_r + dxyz[n][0];
+ int g = idx_g + dxyz[n][1];
+ int b = idx_b + dxyz[n][2];
+
+ if (!IN_RANGE_EXC (r, 0, Red_levels )) continue;
+ if (!IN_RANGE_EXC (g, 0, Green_levels)) continue;
+ if (!IN_RANGE_EXC (b, 0, Blue_levels )) continue;
+
+ unsigned int index = colorcube_index (r, g, b);
+
+ if (rgb24_color[index] == color)
+ {
+ rgb24_seqno[index] = ++rgb24_sequence;
+ return index + minTermCOLOR24;
+ }
+
+ // minor issue: could update index 0 few more times
+ if ((rgb24_seqno[index] | rgb24_color[index]) == 0)
+ {
+ idx = index;
+ goto update;
+ }
+
+ // like (rgb24_seqno[idx] > rgb24_seqno[index])
+ // but also handles wrap around values good enough
+ if ((uint16_t)(rgb24_seqno[idx] - rgb24_seqno[index]) < 0x7fff)
+ idx = index;
+ }
+
+update:
+ rgb24_color[idx] = color;
+ rgb24_seqno[idx] = ++rgb24_sequence;
+
+ idx += minTermCOLOR24;
+ pix_colors_focused [idx].free (this);
+ pix_colors_focused [idx].set (this, rgba (r * 0x0101, g * 0x0101, b * 0x0101, a * 0x0101));
+ update_fade_color (idx, false);
+
+ return idx;
+}
+
void
rxvt_term::process_color_seq (int report, int color, const char *str, char resp)
{
@@ -3477,74 +3535,6 @@
process_color_seq (op, Color_border, str, resp);
break;
-#if BG_IMAGE_FROM_ROOT
- case URxvt_Color_tint:
- process_color_seq (op, Color_tint, str, resp);
- {
- bool changed = false;
-
- if (ISSET_PIXCOLOR (Color_tint))
- changed = root_effects.set_tint (pix_colors_focused [Color_tint]);
-
- if (changed)
- update_background ();
- }
-
- break;
-#endif
-
-#if BG_IMAGE_FROM_FILE
- case Rxvt_Pixmap:
- if (!strcmp (str, "?"))
- {
- char str[256];
- int h_scale = fimage.h_scale;
- int v_scale = fimage.v_scale;
- int h_align = fimage.h_align;
- int v_align = fimage.v_align;
-
- sprintf (str, "[%dx%d+%d+%d]",
- h_scale, v_scale,
- h_align, v_align);
- process_xterm_seq (XTerm_title, str, CHAR_ST);
- }
- else
- {
- bool changed = false;
-
- if (*str != ';')
- {
- try
- {
- fimage.set_file_geometry (this, str);
- changed = true;
- }
- catch (const class rxvt_failure_exception &e)
- {
- }
- }
- else
- {
- str++;
- if (fimage.set_geometry (str, true))
- changed = true;
- }
-
- if (changed)
- {
- if (bg_window_position_sensitive ())
- {
- int x, y;
- get_window_origin (x, y);
- parent_x = x;
- parent_y = y;
- }
- update_background ();
- }
- }
- break;
-#endif
-
case XTerm_logfile:
// TODO, when secure mode?
break;
@@ -3709,6 +3699,7 @@
{ 1002, PrivMode_MouseBtnEvent },
{ 1003, PrivMode_MouseAnyEvent },
#if ENABLE_FRILLS
+ { 1004, PrivMode_FocusEvent },
{ 1005, PrivMode_ExtModeMouse },
#endif
{ 1010, PrivMode_TtyOutputInh }, // rxvt extension
@@ -3965,13 +3956,6 @@
case 37:
scr_color ((unsigned int) (minCOLOR + (arg[i] - 30)), Color_fg);
break;
- case 38: // set fg color, ISO 8613-6
- if (nargs > i + 2 && arg[i + 1] == 5)
- {
- scr_color ((unsigned int) (minCOLOR + arg[i + 2]), Color_fg);
- i += 2;
- }
- break;
case 39: /* default fg */
scr_color (Color_fg, Color_fg);
break;
@@ -3986,17 +3970,39 @@
case 47:
scr_color ((unsigned int) (minCOLOR + (arg[i] - 40)), Color_bg);
break;
- case 48: // set bg color, ISO 8613-6
- if (nargs > i + 2 && arg[i + 1] == 5)
- {
- scr_color ((unsigned int) (minCOLOR + arg[i + 2]), Color_bg);
- i += 2;
- }
- break;
case 49: /* default bg */
scr_color (Color_bg, Color_bg);
break;
+ case 38: // set fg color, ISO 8613-6
+ case 48: // set bg color, ISO 8613-6
+ {
+ unsigned int fgbg = arg[i] == 38 ? Color_fg : Color_bg;
+ unsigned int idx;
+
+ if (nargs > i + 2 && arg[i + 1] == 5)
+ {
+ idx = minCOLOR + arg[i + 2];
+ i += 2;
+
+ scr_color (idx, fgbg);
+ }
+ else if (nargs > i + 4 && arg[i + 1] == 2)
+ {
+ unsigned int r = arg[i + 2];
+ unsigned int g = arg[i + 3];
+ unsigned int b = arg[i + 4];
+ unsigned int a = 0xff;
+
+ idx = map_rgb24_color (r, g, b, a);
+
+ i += 4;
+
+ scr_color (idx, fgbg);
+ }
+ }
+ break;
+
//case 50: // not variable spacing
#if !ENABLE_MINIMAL
--- rxvt-unicode/src/init.C
+++ rxvt-unicode/src/init.C
@@ -153,6 +153,31 @@
}
#endif
+#define NULL_5 \
+ NULL, \
+ NULL, \
+ NULL, \
+ NULL, \
+ NULL,
+
+#define NULL_10 \
+ NULL_5 \
+ NULL_5
+
+#define NULL_40 \
+ NULL_10 \
+ NULL_10 \
+ NULL_10 \
+ NULL_10
+
+#define NULL_50 \
+ NULL_40 \
+ NULL_10
+
+#define NULL_100 \
+ NULL_50 \
+ NULL_50
+
static const char *const def_colorName[] =
{
COLOR_FOREGROUND,
@@ -258,6 +283,12 @@
"rgb:b9/b9/b9",
"rgb:d0/d0/d0",
"rgb:e7/e7/e7",
+ NULL_100
+ NULL_40
+ NULL,
+ NULL,
+ NULL,
+ NULL,
#else
// 256 xterm colours
"rgb:00/00/00",
@@ -500,6 +531,10 @@
"rgb:da/da/da",
"rgb:e4/e4/e4",
"rgb:ee/ee/ee",
+ NULL_100
+ NULL_100
+ NULL_40
+ NULL_5
#endif
#ifndef NO_CURSORCOLOR
@@ -526,9 +561,6 @@
#ifdef RXVT_SCROLLBAR
COLOR_SCROLLTROUGH,
#endif
-#if BG_IMAGE_FROM_ROOT
- NULL,
-#endif
#if OFF_FOCUS_FADING
"rgb:00/00/00",
#endif
@@ -568,6 +600,14 @@
set_option (Opt_buffered);
}
+#if ENABLE_PERL
+static void
+rxvt_perl_parse_resource (rxvt_term *term, const char *k, const char *v)
+{
+ rxvt_perl.parse_resource (term, k, false, false, 0, v);
+}
+#endif
+
/*----------------------------------------------------------------------*/
const char **
rxvt_term::init_resources (int argc, const char *const *argv)
@@ -615,6 +655,7 @@
|| (rs[Rs_perl_eval] && *rs[Rs_perl_eval]))
{
rxvt_perl.init (this);
+ enumerate_resources (rxvt_perl_parse_resource);
HOOK_INVOKE ((this, HOOK_INIT, DT_END));
}
#endif
@@ -824,10 +865,6 @@
if (option (Opt_scrollBar))
scrollBar.resize (); /* create and map scrollbar */
-#ifdef HAVE_BG_PIXMAP
- bg_init ();
-#endif
-
#if ENABLE_PERL
rootwin_ev.start (display, display->root);
#endif
--- rxvt-unicode/src/main.C
+++ rxvt-unicode/src/main.C
@@ -153,9 +153,6 @@
rxvt_term::rxvt_term ()
{
-#if HAVE_BG_PIXMAP
- update_background_ev.set<rxvt_term, &rxvt_term::update_background_cb> (this);
-#endif
#ifdef CURSOR_BLINK
cursor_blink_ev.set <rxvt_term, &rxvt_term::cursor_blink_cb> (this); cursor_blink_ev.set (0., CURSOR_BLINK_INTERVAL);
#endif
@@ -171,7 +168,7 @@
#if defined(MOUSE_WHEEL) && defined(MOUSE_SLIP_WHEELING)
slip_wheel_ev.set <rxvt_term, &rxvt_term::slip_wheel_cb> (this);
#endif
-#if BG_IMAGE_FROM_ROOT || ENABLE_PERL
+#if ENABLE_PERL
rootwin_ev.set <rxvt_term, &rxvt_term::rootwin_cb> (this),
#endif
scrollbar_ev.set <rxvt_term, &rxvt_term::x_cb> (this),
@@ -225,10 +222,6 @@
#endif
delete fontset[0];
-#ifdef HAVE_BG_PIXMAP
- bg_destroy ();
-#endif
-
#if HAVE_IMG
delete bg_img;
#endif
@@ -329,7 +322,7 @@
im_ev.stop (display);
#endif
scrollbar_ev.stop (display);
-#if BG_IMAGE_FROM_ROOT || ENABLE_PERL
+#if ENABLE_PERL
rootwin_ev.stop (display);
#endif
termwin_ev.stop (display);
@@ -1024,7 +1017,7 @@
if (pix_colors[Color_bg] == pix_colors[i])
{
sprintf (bstr, "%d", i - Color_Black);
-#if BG_IMAGE_FROM_FILE
+#if HAVE_IMG
xpmb = "default;";
#endif
break;
@@ -1054,6 +1047,25 @@
pix_colors[dst].set (this, rs[Rs_color + dst] = rs[Rs_color + src]);
}
+#ifdef SMART_RESIZE
+static unsigned int
+get_parent_bw (Display *dpy, Window w)
+{
+ int idummy;
+ unsigned int udummy;
+ Window wdummy, parent;
+ Window *children;
+ unsigned int nchildren, border_width;
+
+ XQueryTree (dpy, w, &wdummy, &parent, &children, &nchildren);
+ XFree (children);
+ XGetGeometry (dpy, parent, &wdummy, &idummy, &idummy,
+ &udummy, &udummy, &border_width, &udummy);
+
+ return border_width;
+}
+#endif
+
/* -------------------------------------------------------------------- *
* - WINDOW RESIZING - *
* -------------------------------------------------------------------- */
@@ -1098,8 +1110,10 @@
*/
if (x1 != x || y1 != y)
{
- x -= x1;
- y -= y1;
+ unsigned int border_width = get_parent_bw (dpy, parent);
+
+ x -= x1 + border_width;
+ y -= y1 + border_width;
}
x1 = (DisplayWidth (dpy, display->screen) - old_width ) / 2;
@@ -1139,11 +1153,6 @@
vt_width, vt_height);
HOOK_INVOKE ((this, HOOK_SIZE_CHANGE, DT_INT, newwidth, DT_INT, newheight, DT_END));
-
-#ifdef HAVE_BG_PIXMAP
- if (bg_window_size_sensitive ())
- update_background ();
-#endif
}
if (fix_screen || old_height == 0)
@@ -1686,32 +1695,4 @@
XTranslateCoordinates (dpy, parent, display->root, 0, 0, &x, &y, &cr);
}
-#ifdef HAVE_BG_PIXMAP
-
-void
-rxvt_term::update_background ()
-{
- if (update_background_ev.is_active ())
- return;
-
- ev_tstamp to_wait = 0.5 - (ev::now () - bg_valid_since);
-
- if (to_wait <= 0.)
- bg_render ();
- else
- update_background_ev.start (to_wait);
-}
-
-void
-rxvt_term::update_background_cb (ev::timer &w, int revents)
-{
- make_current ();
-
- update_background_ev.stop ();
- bg_render ();
- refresh_check ();
-}
-
-#endif /* HAVE_BG_PIXMAP */
-
/*----------------------- end-of-file (C source) -----------------------*/
--- rxvt-unicode/src/Makefile.in
+++ rxvt-unicode/src/Makefile.in
@@ -36,7 +36,7 @@
dummy:
COMMON = \
- background.o command.o rxvtfont.o init.o main.o misc.o \
+ command.o rxvtfont.o init.o main.o misc.o \
screen.o scrollbar.o scrollbar-next.o scrollbar-rxvt.o \
scrollbar-xterm.o scrollbar-plain.o xdefaults.o encoding.o \
rxvttoolkit.o rxvtutil.o keyboard.o rxvtimg.o \
--- rxvt-unicode/src/perl/background
+++ rxvt-unicode/src/perl/background
@@ -3,6 +3,16 @@
#:META:RESOURCE:%.expr:string:background expression
#:META:RESOURCE:%.border:boolean:respect the terminal border
#:META:RESOURCE:%.interval:seconds:minimum time between updates
+#:META:RESOURCE:pixmap:file[;geom]:set image as background
+#:META:RESOURCE:backgroundPixmap:file[;geom]:set image as background
+#:META:RESOURCE:tr:boolean:set root pixmap as background
+#:META:RESOURCE:transparent:boolean:set root pixmap as background
+#:META:RESOURCE:tint:color:tint background with color
+#:META:RESOURCE:tintColor:color:tint background with color
+#:META:RESOURCE:sh:number:shade background by number %
+#:META:RESOURCE:shading:number:shade background by number %
+#:META:RESOURCE:blr:HxV:gaussian-blur background with radii
+#:META:RESOURCE:blurRadius:HxV:gaussian-blur background with radii
=head1 NAME
@@ -134,7 +144,7 @@
scale 2, load "$HOME/mypic.png"
This enlarges the image by a factor of 2 (200%). As you can see, C<scale>
-has now two arguments, the C<200> and the C<load> expression, while
+has now two arguments, the C<2> and the C<load> expression, while
C<load> only has one argument. Arguments are separated from each other by
commas.
@@ -1024,6 +1034,147 @@
is sensitive to some event (root background changes, window geometry
changes), then it will be reevaluated automatically as needed.
+=back
+
+=head1 OLD BACKGROUND IMAGE SETTINGS
+
+This extension also provides support for the old options/resources and
+OSC sequences for setting a background image. These settings are
+B<deprecated> and will be removed in future versions.
+
+=head2 OPTIONS AND RESOURCES
+
+=over 4
+
+=item B<-pixmap> I<file[;oplist]>
+
+=item B<backgroundPixmap:> I<file[;oplist]>
+
+Use the specified image file as the window's background and also
+optionally specify a colon separated list of operations to modify it.
+Note that you may need to quote the C<;> character when using the
+command line option, as C<;> is usually a metacharacter in shells.
+Supported operations are:
+
+=over 4
+
+=item B<WxH+X+Y>
+
+sets scale and position. B<"W" / "H"> specify the horizontal/vertical
+scale (percent), and B<"X" / "Y"> locate the image centre (percent). A
+scale of 0 disables scaling.
+
+=item B<op=tile>
+
+enables tiling
+
+=item B<op=keep-aspect>
+
+maintain the image aspect ratio when scaling
+
+=item B<op=root-align>
+
+use the position of the terminal window relative to the root window as
+the image offset, simulating a root window background
+
+=back
+
+The default scale and position setting is C<100x100+50+50>.
+Alternatively, a predefined set of templates can be used to achieve
+the most common setups:
+
+=over 4
+
+=item B<style=tiled>
+
+the image is tiled with no scaling. Equivalent to 0x0+0+0:op=tile
+
+=item B<style=aspect-stretched>
+
+the image is scaled to fill the whole window maintaining the aspect
+ratio and centered. Equivalent to 100x100+50+50:op=keep-aspect
+
+=item B<style=stretched>
+
+the image is scaled to fill the whole window. Equivalent to 100x100
+
+=item B<style=centered>
+
+the image is centered with no scaling. Equivalent to 0x0+50+50
+
+=item B<style=root-tiled>
+
+the image is tiled with no scaling and using 'root' positioning.
+Equivalent to 0x0:op=tile:op=root-align
+
+=back
+
+If multiple templates are specified the last one wins. Note that a
+template overrides all the scale, position and operations settings.
+
+If used in conjunction with pseudo-transparency, the specified image
+will be blended over the transparent background using alpha-blending.
+
+=item B<-tr>|B<+tr>
+
+=item B<transparent:> I<boolean>
+
+Turn on/off pseudo-transparency by using the root pixmap as background.
+
+=item B<-tint> I<colour>
+
+=item B<tintColor:> I<colour>
+
+Tint the transparent background with the given colour. Note that a
+black tint yields a completely black image while a white tint yields
+the image unchanged.
+
+=item B<-sh> I<number>
+
+=item B<shading:> I<number>
+
+Darken (0 .. 99) or lighten (101 .. 200) the transparent background.
+A value of 100 means no shading.
+
+=item B<-blr> I<HxV>
+
+=item B<blurRadius:> I<HxV>
+
+Apply gaussian blur with the specified radius to the transparent
+background. If a single number is specified, the vertical and
+horizontal radii are considered to be the same. Setting one of the
+radii to 1 and the other to a large number creates interesting effects
+on some backgrounds. The maximum radius value is 128. An horizontal or
+vertical radius of 0 disables blurring.
+
+=back
+
+=head2 OSC sequences
+
+=over 4
+
+=item B<< C<ESC ] 705 ; Pt ST> >> Change transparent background tint colour to B<< C<Pt> >>.
+
+=item B<< C<ESC ] 20 ; Pt ST> >> Change/Query background image
+parameters: the value of B<< C<Pt> >> can be one of the following
+commands:
+
+=over 4
+
+=item B<< C<?> >>
+
+display scale and position in the title
+
+=item B<< C<;WxH+X+Y> >>
+
+change scale and/or position
+
+=item B<< C<FILE;WxH+X+Y> >>
+
+change background image
+
+=back
+
=cut
sub keep(&) {
@@ -1192,11 +1343,215 @@
$self->want_refresh;
}
+sub old_bg_opts {
+ my ($self, $arg) = @_;
+
+ $arg or return;
+
+ my @str = split /;/, $arg;
+
+ return unless $str[0] or $self->{bg_opts}->{path};
+
+ my $bg_opts = $self->{bg_opts};
+
+ if ($str[0]) {
+ $bg_opts->{tile} = 0;
+ $bg_opts->{keep_aspect} = 0;
+ $bg_opts->{root_align} = 0;
+ $bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
+ $bg_opts->{h_align} = $bg_opts->{v_align} = 50;
+ $bg_opts->{path} = unpack "H*", $str[0];
+ }
+
+ my @oplist = split /:/, $str[1];
+
+ for (@oplist) {
+ if (/style=tiled/i) {
+ $bg_opts->{tile} = 1;
+ $bg_opts->{keep_aspect} = 0;
+ $bg_opts->{root_align} = 0;
+ $bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
+ $bg_opts->{h_align} = $bg_opts->{v_align} = 0;
+ } elsif (/style=aspect-stretched/i) {
+ $bg_opts->{tile} = 0;
+ $bg_opts->{keep_aspect} = 1;
+ $bg_opts->{root_align} = 0;
+ $bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
+ $bg_opts->{h_align} = $bg_opts->{v_align} = 50;
+ } elsif (/style=stretched/i) {
+ $bg_opts->{tile} = 0;
+ $bg_opts->{keep_aspect} = 0;
+ $bg_opts->{root_align} = 0;
+ $bg_opts->{h_scale} = $bg_opts->{v_scale} = 100;
+ $bg_opts->{h_align} = $bg_opts->{v_align} = 50;
+ } elsif (/style=centered/i) {
+ $bg_opts->{tile} = 0;
+ $bg_opts->{keep_aspect} = 0;
+ $bg_opts->{root_align} = 0;
+ $bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
+ $bg_opts->{h_align} = $bg_opts->{v_align} = 50;
+ } elsif (/style=root-tiled/i) {
+ $bg_opts->{tile} = 1;
+ $bg_opts->{keep_aspect} = 0;
+ $bg_opts->{root_align} = 1;
+ $bg_opts->{h_scale} = $bg_opts->{v_scale} = 0;
+ $bg_opts->{h_align} = $bg_opts->{v_align} = 0;
+ } elsif (/op=tile/i) {
+ $bg_opts->{tile} = 1;
+ } elsif (/op=keep_aspect/i) {
+ $bg_opts->{keep_aspect} = 1;
+ } elsif (/op=root_align/i) {
+ $bg_opts->{root_align} = 1;
+ } elsif (/^ =? ([0-9]+)? (?:[xX] ([0-9]+))? ([+-][0-9]+)? ([+-][0-9]+)? $/x) {
+ my ($w, $h, $x, $y) = ($1, $2, $3, $4);
+
+ if ($str[0]) {
+ $w = $h unless defined $w;
+ $h = $w unless defined $h;
+ $y = $x unless defined $y;
+ }
+
+ $bg_opts->{h_scale} = $w if defined $w;
+ $bg_opts->{v_scale} = $h if defined $h;
+ $bg_opts->{h_align} = $x if defined $x;
+ $bg_opts->{v_align} = $y if defined $y;
+ }
+ }
+}
+
+sub old_bg_expr {
+ my ($self) = @_;
+
+ my $expr;
+
+ my $bg_opts = $self->{bg_opts};
+
+ if ($bg_opts->{root} =~ /^\s*(?:true|yes|on|1)\s*$/i) {
+ $expr .= "tile (";
+
+ my $shade = $bg_opts->{shade};
+
+ if ($shade) {
+ $shade = List::Util::min $shade, 200;
+ $shade = List::Util::max $shade, -100;
+ $shade = 200 - (100 + $shade) if $shade < 0;
+
+ $shade = $shade * 0.01 - 1;
+ $expr .= "shade $shade, ";
+ }
+
+ my $tint = $bg_opts->{tint};
+
+ if ($tint) {
+ $expr .= "tint $tint, ";
+ }
+
+ my $blur = $bg_opts->{blur};
+
+ if ($blur and $blur =~ /^ =? ([0-9]+)? (?:[xX] ([0-9]+))? $/x) {
+ my $hr = defined $1 ? $1 : 1;
+ my $vr = defined $2 ? $2 : $hr;
+
+ if ($hr != 0 and $vr != 0) {
+ $expr .= "blur $hr, $vr, ";
+ }
+ }
+
+ $expr .= "rootalign root)";
+ }
+
+ if ($bg_opts->{path}) {
+ my $file_expr;
+ my $h_scale = $bg_opts->{h_scale} * 0.01;
+ my $v_scale = $bg_opts->{v_scale} * 0.01;
+ my $h_align = $bg_opts->{h_align} * 0.01;
+ my $v_align = $bg_opts->{v_align} * 0.01;
+
+ if (!$bg_opts->{tile}) {
+ $file_expr .= "pad (";
+ } else {
+ $file_expr .= "tile (";
+ }
+
+ if ($bg_opts->{root_align}) {
+ $file_expr .= "rootalign ";
+ } else {
+ $file_expr .= "align $h_align, $v_align, ";
+ }
+
+ if ($h_scale != 0 and $v_scale != 0) {
+ my $op = $bg_opts->{keep_aspect} ? "fit" : "resize";
+ $file_expr .= "$op TW * $h_scale, TH * $v_scale, ";
+ }
+
+ $file_expr .= "keep { load pack \"H*\", \"$bg_opts->{path}\" })";
+
+ if ($expr) {
+ $expr .= ", tint (\"[50]white\", $file_expr)";
+ } else {
+ $expr = $file_expr;
+ }
+ }
+
+ $expr
+}
+
+sub on_osc_seq {
+ my ($self, $op, $arg) = @_;
+
+ $self->{bg_opts} or return;
+
+ $op =~ /^(20|705)$/ or return;
+
+ if ($op eq "20") {
+ if ($arg eq "?") {
+ my $h_scale = $self->{bg_opts}->{h_scale};
+ my $v_scale = $self->{bg_opts}->{v_scale};
+ my $h_align = $self->{bg_opts}->{h_align};
+ my $v_align = $self->{bg_opts}->{v_align};
+ $self->cmd_parse ("\033]2;[${h_scale}x${v_scale}+${h_align}+${v_align}]\007");
+ } else {
+ $self->old_bg_opts ($arg);
+ my $expr = $self->old_bg_expr;
+ $self->set_expr (parse_expr $expr) if $expr;
+ }
+ } elsif ($op eq "705") {
+ $self->{bg_opts}->{tint} = $arg;
+ my $expr = $self->old_bg_expr;
+ $self->set_expr (parse_expr $expr) if $expr;
+ }
+
+ 1
+}
+
+sub find_resource {
+ my ($self, $res, $opt) = @_;
+
+ my $v = $self->x_resource ($opt);
+ $v = $self->x_resource ($res) unless defined $v;
+
+ $v
+}
+
sub on_start {
my ($self) = @_;
- my $expr = $self->x_resource ("%.expr")
- or return;
+ my $expr = $self->x_resource ("%.expr");
+
+ if (!$expr) {
+ $self->{bg_opts} = { h_scale => 100, v_scale => 100,
+ h_align => 50, v_align => 50 };
+
+ $self->{bg_opts}->{shade} = $self->find_resource ("shading", "sh");
+ $self->{bg_opts}->{tint} = $self->find_resource ("tintColor", "tint");
+ $self->{bg_opts}->{blur} = $self->find_resource ("blurRadius", "blr");
+ $self->{bg_opts}->{root} = $self->find_resource ("transparent", "tr");
+
+ $self->old_bg_opts ($self->find_resource ("backgroundPixmap", "pixmap"));
+ $expr = $self->old_bg_expr;
+ }
+
+ $expr or return;
$self->has_render
or die "background extension needs RENDER extension 0.10 or higher, ignoring background-expr.\n";
--- rxvt-unicode/src/perl/kuake
+++ rxvt-unicode/src/perl/kuake
@@ -8,7 +8,7 @@
=head1 EXAMPLES
- @@RXVT_NAME@@ -kuake-hotkey F10
+ urxvt -kuake-hotkey F10
URxvt.kuake.hotkey: F10
--- rxvt-unicode/src/perl/searchable-scrollback
+++ rxvt-unicode/src/perl/searchable-scrollback
@@ -16,12 +16,49 @@
suspended and a regex is displayed at the bottom of the screen.
Inputting characters appends them to the regex and continues incremental
-search. C<BackSpace> removes a character from the regex, C<Up> and C<Down>
-search upwards/downwards in the scrollback buffer, C<End> jumps to the
-bottom. C<Escape> leaves search mode and returns to the point where search
-was started, while C<Enter> or C<Return> stay at the current position and
-additionally stores the first match in the current line into the primary
-selection if the C<Shift> modifier is active.
+search. In addition, the following bindings are recognized:
+
+=over 4
+
+=item C<BackSpace>
+
+Remove a character from the regex.
+
+=item C<Insert>
+
+Append the value of the PRIMARY selection to the regex.
+
+=item C<Up>
+
+Search for a match upwards.
+
+=item C<Down>
+
+Search for a match downwards.
+
+=item C<Prior>
+
+Scroll up.
+
+=item C<Next>
+
+Scroll down.
+
+=item C<End>
+
+Scroll to the bottom.
+
+=item C<Escape>
+
+Leave the mode and return to the point where search was started.
+
+=item C<Enter> or C<Return>
+
+Leave the mode maintaining the current position in the scrollback.
+Additionally, if the C<Shift> modifier is active, store the first
+match in the current line into the primary selection.
+
+=back
The regex defaults to "(?i)", resulting in a case-insensitive search. To
get a case-sensitive search you can delete this prefix using C<BackSpace>
@@ -184,6 +221,14 @@
my $line = $self->line ($self->{row});
$self->search (+1, $line->end + 1)
if $line->end < $self->nrow;
+ } elsif ($keysym == 0xff55) { # prior
+ my $row = $self->view_start - ($self->nrow - 1);
+ $self->view_start (List::Util::min 0, $row);
+ } elsif ($keysym == 0xff56) { # next
+ my $row = $self->view_start + ($self->nrow - 1);
+ $self->view_start (List::Util::min 0, $row);
+ } elsif ($keysym == 0xff63) { # insert
+ $self->selection_request (urxvt::CurrentTime, 1);
} elsif ($keysym == 0xff08) { # backspace
substr $self->{search}, -1, 1, "";
$self->search (+1, $self->{row});
--- rxvt-unicode/src/perl/tabbed
+++ rxvt-unicode/src/perl/tabbed
@@ -31,7 +31,7 @@
URxvt.tabbed.tab-fg: <colour-index, default 0>
URxvt.tabbed.tab-bg: <colour-index, default 1>
-See I<COLOR AND GRAPHICS> in the @@RXVT_NAME@@(1) manpage for valid
+See I<COLOR AND GRAPHICS> in the urxvt(1) manpage for valid
indices.
=cut
--- rxvt-unicode/src/rsinc.h
+++ rxvt-unicode/src/rsinc.h
@@ -17,10 +17,6 @@
#endif
def (name)
def (title)
-#if BG_IMAGE_FROM_FILE
- def (path)
- def (backgroundPixmap)
-#endif
def (loginShell)
def (multiClickTime)
def (jumpScroll)
@@ -59,11 +55,6 @@
def (preeditType)
def (inputMethod)
#endif
-#if BG_IMAGE_FROM_ROOT
- def (transparent)
- def (shade)
- def (blurradius)
-#endif
#if XFT
def (buffered)
#endif
--- rxvt-unicode/src/rxvtfont.C
+++ rxvt-unicode/src/rxvtfont.C
@@ -241,7 +241,7 @@
#if XFT
Picture dst;
-# ifdef HAVE_BG_PIXMAP
+# ifdef HAVE_IMG
if (term->bg_img
&& !term->pix_colors[color].is_opaque ()
&& ((dst = XftDrawPicture (d))))
@@ -1412,7 +1412,7 @@
{
rxvt_drawable &d2 = d.screen->scratch_drawable (w, h);
-#ifdef HAVE_BG_PIXMAP
+#ifdef HAVE_IMG
Picture dst = 0; // the only assignment is done conditionally in the following if condition
if (term->bg_img
--- rxvt-unicode/src/rxvtfont.h
+++ rxvt-unicode/src/rxvtfont.h
@@ -73,9 +73,9 @@
// must be power-of-two - 1, also has to match RS_fontMask in rxvt.h
#if USE_256_COLORS
- enum { fontCount = 7 }; // 4 extra colors bits, 4 fewer fontcount bits
+ enum { fontCount = 7 }; // 2 extra colors bits, 2 fewer fontcount bits
#else
- enum { fontCount = 127 };
+ enum { fontCount = 31 };
#endif
// index of first font in set
--- rxvt-unicode/src/rxvt.h
+++ rxvt-unicode/src/rxvt.h
@@ -77,19 +77,9 @@
#endif
#if XRENDER && (HAVE_PIXBUF || ENABLE_TRANSPARENCY)
-# define HAVE_BG_PIXMAP 1
# define HAVE_IMG 1
#endif
-#if HAVE_BG_PIXMAP
-# if HAVE_PIXBUF
-# define BG_IMAGE_FROM_FILE 1
-# endif
-# if ENABLE_TRANSPARENCY
-# define BG_IMAGE_FROM_ROOT 1
-# endif
-#endif
-
#include <ecb.h>
#include "encoding.h"
#include "rxvtutil.h"
@@ -214,85 +204,6 @@
}
};
-#ifdef HAVE_BG_PIXMAP
-struct image_effects
-{
- bool tint_set;
- rxvt_color tint;
- int shade;
- int h_blurRadius, v_blurRadius;
-
- image_effects ()
- {
- tint_set =
- h_blurRadius =
- v_blurRadius = 0;
- shade = 100;
- }
-
- bool need_tint ()
- {
- return shade != 100 || tint_set;
- }
-
- bool need_blur ()
- {
- return h_blurRadius && v_blurRadius;
- }
-
- bool set_tint (const rxvt_color &new_tint);
- bool set_shade (const char *shade_str);
- bool set_blur (const char *geom);
-};
-
-# if BG_IMAGE_FROM_FILE
-enum {
- IM_IS_SIZE_SENSITIVE = 1 << 1,
- IM_KEEP_ASPECT = 1 << 2,
- IM_ROOT_ALIGN = 1 << 3,
- IM_TILE = 1 << 4,
- IM_GEOMETRY_FLAGS = IM_KEEP_ASPECT | IM_ROOT_ALIGN | IM_TILE,
-};
-
-enum {
- noScale = 0,
- windowScale = 100,
- defaultScale = windowScale,
- centerAlign = 50,
- defaultAlign = centerAlign,
-};
-
-struct rxvt_image : image_effects
-{
- unsigned short alpha;
- uint8_t flags;
- unsigned int h_scale, v_scale; /* percents of the window size */
- int h_align, v_align; /* percents of the window size:
- 0 - left align, 50 - center, 100 - right */
-
- bool is_size_sensitive ()
- {
- return (!(flags & IM_TILE)
- || h_scale || v_scale
- || (!(flags & IM_ROOT_ALIGN) && (h_align || v_align)));
- }
-
- rxvt_img *img;
-
- void destroy ()
- {
- delete img;
- img = 0;
- }
-
- rxvt_image ();
- void set_file_geometry (rxvt_screen *s, const char *file);
- void set_file (rxvt_screen *s, const char *file);
- bool set_geometry (const char *geom, bool update = false);
-};
-# endif
-#endif
-
/*
*****************************************************************************
* STRUCTURES AND TYPEDEFS
@@ -344,7 +255,7 @@
/* COLORTERM, TERM environment variables */
#define COLORTERMENV "rxvt"
-#if BG_IMAGE_FROM_FILE
+#if HAVE_IMG
# define COLORTERMENVFULL COLORTERMENV "-xpm"
#else
# define COLORTERMENVFULL COLORTERMENV
@@ -357,6 +268,23 @@
# endif
#endif
+// Hidden color cube for indexed 24-bit colors. There are fewer blue levels
+// because normal human eye is less sensitive to the blue component than to
+// the red or green. (https://en.m.wikipedia.org/wiki/Color_depth#8-bit_color)
+#if USE_256_COLORS
+// 7x7x5=245 < 254 unused color indices
+# define Red_levels 7
+# define Green_levels 7
+# define Blue_levels 5
+#else
+// 6x6x4=144 < 166 unused color indices
+# define Red_levels 6
+# define Green_levels 6
+# define Blue_levels 4
+#endif
+
+#define RGB24_CUBE_SIZE (Red_levels * Green_levels * Blue_levels)
+
#if defined (NO_MOUSE_REPORT) && !defined (NO_MOUSE_REPORT_SCROLLBAR)
# define NO_MOUSE_REPORT_SCROLLBAR 1
#endif
@@ -495,14 +423,12 @@
Rxvt_restoreFG = 39,
Rxvt_restoreBG = 49,
- Rxvt_Pixmap = 20, // new bg pixmap
Rxvt_dumpscreen = 55, // dump scrollback and all of screen
URxvt_locale = 701, // change locale
URxvt_version = 702, // request version
URxvt_Color_IT = 704, // change actual 'Italic' colour
- URxvt_Color_tint = 705, // change actual tint colour
URxvt_Color_BD = 706, // change actual 'Bold' color
URxvt_Color_UL = 707, // change actual 'Underline' color
URxvt_Color_border = 708,
@@ -560,6 +486,9 @@
#else
maxTermCOLOR = Color_White + 72,
#endif
+ minTermCOLOR24,
+ maxTermCOLOR24 = minTermCOLOR24 +
+ RGB24_CUBE_SIZE - 1,
#ifndef NO_CURSORCOLOR
Color_cursor,
Color_cursor2,
@@ -584,9 +513,6 @@
#ifdef RXVT_SCROLLBAR
Color_trough,
#endif
-#if BG_IMAGE_FROM_ROOT
- Color_tint,
-#endif
#if OFF_FOCUS_FADING
Color_fade,
#endif
@@ -601,9 +527,13 @@
};
#if USE_256_COLORS
-# define Color_Bits 9 // 0 .. maxTermCOLOR
+# define Color_Bits 9 // 0 .. maxTermCOLOR24
#else
-# define Color_Bits 7 // 0 .. maxTermCOLOR
+# define Color_Bits 8 // 0 .. maxTermCOLOR24
+#endif
+
+#if maxTermCOLOR24 >= (1 << Color_Bits)
+# error color index overflow
#endif
/*
@@ -645,6 +575,7 @@
#define PrivMode_ExtModeMouse (1UL<<23) // xterm pseudo-utf-8 hack
#define PrivMode_ExtMouseRight (1UL<<24) // xterm pseudo-utf-8, but works in non-utf-8-locales
#define PrivMode_BlinkingCursor (1UL<<25)
+#define PrivMode_FocusEvent (1UL<<26)
#define PrivMode_mouse_report (PrivMode_MouseX10|PrivMode_MouseX11|PrivMode_MouseBtnEvent|PrivMode_MouseAnyEvent)
@@ -1170,35 +1101,10 @@
static struct termios def_tio;
row_col_t oldcursor;
-#ifdef HAVE_BG_PIXMAP
- void bg_init ();
- void bg_destroy ();
-
-# if BG_IMAGE_FROM_FILE
- rxvt_image fimage;
- void render_image (rxvt_image &image);
-# endif
-
-# if BG_IMAGE_FROM_ROOT
- rxvt_img *root_img;
- image_effects root_effects;
-
- void render_root_image ();
-# endif
-
- ev_tstamp bg_valid_since;
-
- bool bg_window_size_sensitive ();
- bool bg_window_position_sensitive ();
-
- void bg_render ();
-#endif
-
#ifdef HAVE_IMG
enum {
BG_IS_TRANSPARENT = 1 << 1,
BG_NEEDS_REFRESH = 1 << 2,
- BG_INHIBIT_RENDER = 1 << 3,
};
uint8_t bg_flags;
@@ -1249,6 +1155,10 @@
void *chunk;
size_t chunk_size;
+ uint32_t rgb24_color[RGB24_CUBE_SIZE]; // the 24-bit color value
+ uint16_t rgb24_seqno[RGB24_CUBE_SIZE]; // which one is older?
+ uint16_t rgb24_sequence;
+
static vector<rxvt_term *> termlist; // a vector of all running rxvt_term's
#if ENABLE_FRILLS || ISO_14755
@@ -1268,15 +1178,10 @@
XSelectInput (dpy, vt, vt_emask | vt_emask_perl | vt_emask_xim | vt_emask_mouse);
}
-#if BG_IMAGE_FROM_ROOT || ENABLE_PERL
+#if ENABLE_PERL
void rootwin_cb (XEvent &xev);
xevent_watcher rootwin_ev;
#endif
-#ifdef HAVE_BG_PIXMAP
- void update_background ();
- void update_background_cb (ev::timer &w, int revents);
- ev::timer update_background_ev;
-#endif
void x_cb (XEvent &xev);
xevent_watcher termwin_ev;
@@ -1388,6 +1293,7 @@
void process_osc_seq ();
void process_color_seq (int report, int color, const char *str, char resp);
void process_xterm_seq (int op, char *str, char resp);
+ unsigned int map_rgb24_color (unsigned int r, unsigned int g, unsigned int b, unsigned int a);
int privcases (int mode, unsigned long bit);
void process_terminal_mode (int mode, int priv, unsigned int nargs, const int *arg);
void process_sgr_mode (unsigned int nargs, const int *arg);
@@ -1561,7 +1467,11 @@
int bind_action (const char *str, const char *arg);
const char *x_resource (const char *name);
void extract_resources ();
- void enumerate_keysym_resources (void (*cb)(rxvt_term *, const char *, const char *));
+ void enumerate_resources (void (*cb)(rxvt_term *, const char *, const char *), const char *name_p = 0, const char *class_p = 0);
+ void enumerate_keysym_resources (void (*cb)(rxvt_term *, const char *, const char *))
+ {
+ enumerate_resources (cb, "keysym", "Keysym");
+ }
void extract_keysym_resources ();
};
--- rxvt-unicode/src/rxvtimg.C
+++ rxvt-unicode/src/rxvtimg.C
@@ -166,7 +166,7 @@
else if (!this->dstimg->pm) // somewhat unsatisfying
this->dstimg->alloc ();
- dpy = srcimg->s->dpy;
+ dpy = srcimg->d->dpy;
src = srcimg->picture ();
dst = this->dstimg->picture ();
}
@@ -249,13 +249,19 @@
}
rxvt_img::rxvt_img (rxvt_screen *screen, XRenderPictFormat *format, int x, int y, int width, int height, int repeat)
-: s(screen), x(x), y(y), w(width), h(height), format(format), repeat(repeat),
+: d(screen->display), x(x), y(y), w(width), h(height), format(format), repeat(repeat),
+ pm(0), ref(0)
+{
+}
+
+rxvt_img::rxvt_img (rxvt_display *display, XRenderPictFormat *format, int x, int y, int width, int height, int repeat)
+: d(display), x(x), y(y), w(width), h(height), format(format), repeat(repeat),
pm(0), ref(0)
{
}
rxvt_img::rxvt_img (const rxvt_img &img)
-: s(img.s), x(img.x), y(img.y), w(img.w), h(img.h), format(img.format), repeat(img.repeat), pm(img.pm), ref(img.ref)
+: d(img.d), x(img.x), y(img.y), w(img.w), h(img.h), format(img.format), repeat(img.repeat), pm(img.pm), ref(img.ref)
{
++ref->cnt;
}
@@ -416,7 +422,7 @@
return;
if (pm && ref->ours)
- XFreePixmap (s->dpy, pm);
+ XFreePixmap (d->dpy, pm);
delete ref;
}
@@ -429,14 +435,14 @@
void
rxvt_img::alloc ()
{
- pm = XCreatePixmap (s->dpy, s->display->root, w, h, format->depth);
+ pm = XCreatePixmap (d->dpy, d->root, w, h, format->depth);
ref = new pixref (w, h);
}
rxvt_img *
rxvt_img::new_empty ()
{
- rxvt_img *img = new rxvt_img (s, format, x, y, w, h, repeat);
+ rxvt_img *img = new rxvt_img (d, format, x, y, w, h, repeat);
img->alloc ();
return img;
@@ -445,7 +451,7 @@
Picture
rxvt_img::picture ()
{
- Display *dpy = s->dpy;
+ Display *dpy = d->dpy;
XRenderPictureAttributes pa;
pa.repeat = repeat;
@@ -460,10 +466,10 @@
if (ref->cnt == 1 && ref->ours)
return;
- Pixmap pm2 = XCreatePixmap (s->dpy, s->display->root, ref->w, ref->h, format->depth);
- GC gc = XCreateGC (s->dpy, pm, 0, 0);
- XCopyArea (s->dpy, pm, pm2, gc, 0, 0, ref->w, ref->h, 0, 0);
- XFreeGC (s->dpy, gc);
+ Pixmap pm2 = XCreatePixmap (d->dpy, d->root, ref->w, ref->h, format->depth);
+ GC gc = XCreateGC (d->dpy, pm, 0, 0);
+ XCopyArea (d->dpy, pm, pm2, gc, 0, 0, ref->w, ref->h, 0, 0);
+ XFreeGC (d->dpy, gc);
destroy ();
@@ -476,7 +482,7 @@
{
XRenderColor rc = { c.r, c.g, c.b, c.a };
- Display *dpy = s->dpy;
+ Display *dpy = d->dpy;
Picture src = picture ();
XRenderFillRectangle (dpy, PictOpSrc, src, &rc, x, y, w, h);
XRenderFreePicture (dpy, src);
@@ -494,7 +500,7 @@
if (format->direct.alphaMask)
return;
- composer cc (this, new rxvt_img (s, find_alpha_format_for (s->dpy, format), x, y, w, h, repeat));
+ composer cc (this, new rxvt_img (d, find_alpha_format_for (d->dpy, format), x, y, w, h, repeat));
XRenderComposite (cc.dpy, PictOpSrc, cc.src, None, cc.dst, 0, 0, 0, 0, 0, 0, w, h);
@@ -530,10 +536,10 @@
rxvt_img *
rxvt_img::blur (int rh, int rv)
{
- if (!(s->display->flags & DISPLAY_HAS_RENDER_CONV))
+ if (!(d->flags & DISPLAY_HAS_RENDER_CONV))
return clone ();
- Display *dpy = s->dpy;
+ Display *dpy = d->dpy;
int size = max (rh, rv) * 2 + 1;
nv *kernel = (nv *)malloc (size * sizeof (nv));
XFixed *params = rxvt_temp_buf<XFixed> (size + 2);
@@ -594,7 +600,7 @@
{
// STEP 1: double the image width, fill all odd columns with white (==1)
- composer cc (this, new rxvt_img (s, format, 0, 0, w * 2, h, repeat));
+ composer cc (this, new rxvt_img (d, format, 0, 0, w * 2, h, repeat));
// why the hell does XRenderSetPictureTransform want a writable matrix :(
// that keeps us from just static const'ing this matrix.
@@ -671,7 +677,7 @@
{
unshare ();
- Display *dpy = s->dpy;
+ Display *dpy = d->dpy;
Picture dst = XRenderCreatePicture (dpy, pm, format, 0, 0);
// loop should not be needed for brightness, as only -1..1 makes sense
@@ -765,7 +771,7 @@
&& (x || y) // we need one because of non-zero offset
&& repeat == RepeatNone; // and we have no good pixels to fill with
- composer cc (this, new rxvt_img (s, alpha ? find_alpha_format_for (s->dpy, format) : format,
+ composer cc (this, new rxvt_img (d, alpha ? find_alpha_format_for (d->dpy, format) : format,
0, 0, w, h, repeat));
if (repeat == RepeatNone)
@@ -837,7 +843,7 @@
mat3x3 inv = (mat3x3::translate (-x, -y) * m * mat3x3::translate (x, y)).inverse ();
- composer cc (this, new rxvt_img (s, format, nx, ny, new_width, new_height, repeat));
+ composer cc (this, new rxvt_img (d, format, nx, ny, new_width, new_height, repeat));
XTransform xfrm;
@@ -886,7 +892,7 @@
if (new_format == format)
return clone ();
- composer cc (this, new rxvt_img (s, new_format, x, y, w, h, repeat));
+ composer cc (this, new rxvt_img (d, new_format, x, y, w, h, repeat));
int op = PictOpSrc;
--- rxvt-unicode/src/rxvtimg.h
+++ rxvt-unicode/src/rxvtimg.h
@@ -47,13 +47,14 @@
}
};
- rxvt_screen *s;
+ rxvt_display *d;
Pixmap pm;
pixref *ref; // shared refcnt
int x, y, w, h, repeat;
XRenderPictFormat *format;
rxvt_img (rxvt_screen *screen, XRenderPictFormat *format, int x, int y, int width, int height, int repeat = RepeatNormal);
+ rxvt_img (rxvt_display *display, XRenderPictFormat *format, int x, int y, int width, int height, int repeat = RepeatNormal);
rxvt_img (const rxvt_img &img);
void alloc ();
--- rxvt-unicode/src/rxvtperl.xs
+++ rxvt-unicode/src/rxvtperl.xs
@@ -293,7 +293,7 @@
for (; i < AvFILL (overlay_av); i++)
av_store (overlay_av, i, SvREFCNT_inc (*av_fetch (overlay_av, i + 1, 0)));
- av_pop (overlay_av);
+ SvREFCNT_dec (av_pop (overlay_av));
SvREFCNT_dec (overlay_av);
overlay_av = 0;
@@ -1022,6 +1022,36 @@
const_iv (XIMDontChange),
# endif
# endif
+
+ /* DEC private modes */
+ const_iv (PrivMode_132),
+ const_iv (PrivMode_132OK),
+ const_iv (PrivMode_rVideo),
+ const_iv (PrivMode_relOrigin),
+ const_iv (PrivMode_Screen),
+ const_iv (PrivMode_Autowrap),
+ const_iv (PrivMode_aplCUR),
+ const_iv (PrivMode_aplKP),
+ const_iv (PrivMode_HaveBackSpace),
+ const_iv (PrivMode_BackSpace),
+ const_iv (PrivMode_ShiftKeys),
+ const_iv (PrivMode_VisibleCursor),
+ const_iv (PrivMode_MouseX10),
+ const_iv (PrivMode_MouseX11),
+ const_iv (PrivMode_scrollBar),
+ const_iv (PrivMode_TtyOutputInh),
+ const_iv (PrivMode_Keypress),
+ const_iv (PrivMode_smoothScroll),
+ const_iv (PrivMode_vt52),
+ const_iv (PrivMode_LFNL),
+ const_iv (PrivMode_MouseBtnEvent),
+ const_iv (PrivMode_MouseAnyEvent),
+ const_iv (PrivMode_BracketPaste),
+ const_iv (PrivMode_ExtModeMouse),
+ const_iv (PrivMode_ExtMouseRight),
+ const_iv (PrivMode_BlinkingCursor),
+ const_iv (PrivMode_mouse_report),
+ const_iv (PrivMode_Default),
};
for (civ = const_iv + ecb_array_length (const_iv); civ > const_iv; civ--)
@@ -1422,6 +1452,7 @@
ModNumLockMask = 2
current_screen = 3
hidden_cursor = 4
+ priv_modes = 5
CODE:
switch (ix)
{
@@ -1431,7 +1462,10 @@
case 3: RETVAL = THIS->current_screen; break;
#ifdef CURSOR_BLINK
case 4: RETVAL = THIS->hidden_cursor; break;
+#else
+ case 4: RETVAL = 0; break;
#endif
+ case 5: RETVAL = THIS->priv_modes; break;
}
OUTPUT:
RETVAL
@@ -2303,7 +2337,7 @@
->replace (img);
THIS->bg_img = img;
- THIS->bg_flags |= rxvt_term::BG_NEEDS_REFRESH | rxvt_term::BG_INHIBIT_RENDER;
+ THIS->bg_flags |= rxvt_term::BG_NEEDS_REFRESH;
if (!border)
THIS->bg_flags |= rxvt_term::BG_IS_TRANSPARENT;
@@ -2390,7 +2424,9 @@
rxvt_img::fill (SV *c, int x = 0, int y = 0, int w = THIS->w, int h = THIS->h)
PROTOTYPE: $;$$$$
INIT:
- rgba cc = parse_rgba (c, THIS->s);
+ rxvt_screen screen;
+ screen.set (THIS->d);
+ rgba cc = parse_rgba (c, &screen);
C_ARGS: cc, x, y, w, h
void
@@ -2458,7 +2494,9 @@
rxvt_img *
rxvt_img::tint (SV *c)
INIT:
- rgba cc = parse_rgba (c, THIS->s);
+ rxvt_screen screen;
+ screen.set (THIS->d);
+ rgba cc = parse_rgba (c, &screen);
C_ARGS: cc
rxvt_img *
--- rxvt-unicode/src/screen.C
+++ rxvt-unicode/src/screen.C
@@ -617,7 +617,7 @@
void
rxvt_term::scr_color (unsigned int color, int fgbg) NOTHROW
{
- if (!IN_RANGE_INC (color, minCOLOR, maxTermCOLOR))
+ if (!IN_RANGE_INC (color, minCOLOR, maxTermCOLOR24))
color = fgbg;
if (fgbg == Color_fg)
@@ -1716,6 +1716,14 @@
{
rvideo_state = on;
+#if OFF_FOCUS_FADING
+ if (rs[Rs_fade])
+ {
+ ::swap (pix_colors_focused[Color_fg], pix_colors_focused[Color_bg]);
+ ::swap (pix_colors_unfocused[Color_fg], pix_colors_unfocused[Color_bg]);
+ }
+ else
+#endif
::swap (pix_colors[Color_fg], pix_colors[Color_bg]);
#ifdef HAVE_IMG
if (bg_img == 0)
--- rxvt-unicode/src/urxvt.pm
+++ rxvt-unicode/src/urxvt.pm
@@ -514,6 +514,18 @@
Various constants for use in X calls and event processing.
+=item urxvt::PrivMode_132, PrivMode_132OK, PrivMode_rVideo, PrivMode_relOrigin,
+PrivMode_Screen, PrivMode_Autowrap, PrivMode_aplCUR, PrivMode_aplKP,
+PrivMode_HaveBackSpace, PrivMode_BackSpace, PrivMode_ShiftKeys,
+PrivMode_VisibleCursor, PrivMode_MouseX10, PrivMode_MouseX11,
+PrivMode_scrollBar, PrivMode_TtyOutputInh, PrivMode_Keypress,
+PrivMode_smoothScroll, PrivMode_vt52, PrivMode_LFNL, PrivMode_MouseBtnEvent,
+PrivMode_MouseAnyEvent, PrivMode_BracketPaste, PrivMode_ExtModeMouse,
+PrivMode_ExtMouseRight, PrivMode_BlinkingCursor, PrivMode_mouse_report,
+PrivMode_Default
+
+Constants for checking DEC private modes.
+
=back
=head2 RENDITION
@@ -606,6 +618,8 @@
push @{ $term->{perl_ext_3} }, $v->[0];
+ return 1 unless $isarg;
+
if ($v->[1] eq "boolean") {
$term->put_option_db ($name, $flag ? "true" : "false");
return 1;
@@ -1691,6 +1705,16 @@
Returns whether the cursor is currently hidden or not.
+=item $priv_modes = $term->priv_modes
+
+Returns a bitset with the state of DEC private modes.
+
+Example:
+
+ if ($term->priv_modes & urxvt::PrivMode_mouse_report) {
+ # mouse reporting is turned on
+ }
+
=item $view_start = $term->view_start ([$newvalue])
Returns the row number of the topmost displayed line. Maximum value is
--- rxvt-unicode/src/xdefaults.C
+++ rxvt-unicode/src/xdefaults.C
@@ -115,13 +115,6 @@
BOOL (Rs_scrollTtyOutput, NULL, "si", Opt_scrollTtyOutput, Optflag_Reverse, "scroll-on-tty-output inhibit"),
BOOL (Rs_scrollTtyKeypress, "scrollTtyKeypress", "sk", Opt_scrollTtyKeypress, 0, "scroll-on-keypress"),
BOOL (Rs_scrollWithBuffer, "scrollWithBuffer", "sw", Opt_scrollWithBuffer, 0, "scroll-with-buffer"),
-#if BG_IMAGE_FROM_ROOT
- BOOL (Rs_transparent, "inheritPixmap", "ip", Opt_transparent, 0, "inherit parent pixmap"),
- BOOL (Rs_transparent, "transparent", "tr", Opt_transparent, 0, "inherit parent pixmap"),
- STRG (Rs_color + Color_tint, "tintColor", "tint", "color", "tint color"),
- STRG (Rs_shade, "shading", "sh", "number", "shade background by number %."),
- STRG (Rs_blurradius, "blurRadius", "blr", "HxV", "gaussian blur radii to apply to the root background"),
-#endif
#if OFF_FOCUS_FADING
STRG (Rs_fade, "fading", "fade", "number", "fade colors by number % when losing focus"),
STRG (Rs_color + Color_fade, "fadeColor", "fadecolor", "color", "target color for off-focus fading"),
@@ -196,10 +189,6 @@
STRG (Rs_color + Color_pointer_fg, "pointerColor", "pr", "color", "pointer color"),
STRG (Rs_color + Color_pointer_bg, "pointerColor2", "pr2", "color", "pointer bg color"),
STRG (Rs_color + Color_border, "borderColor", "bd", "color", "border color"),
-#if BG_IMAGE_FROM_FILE
- RSTRG (Rs_path, "path", "search path"),
- STRG (Rs_backgroundPixmap, "backgroundPixmap", "pixmap", "file[;geom]", "background pixmap"),
-#endif
#if ENABLE_EWMH
STRG (Rs_iconfile, "iconFile", "icon", "file", "path to application icon image"),
#endif
@@ -646,7 +635,7 @@
* value will be a string
*/
static int
-rxvt_keysym_enumerate_helper (
+rxvt_enumerate_helper (
XrmDatabase *database ecb_unused,
XrmBindingList bindings ecb_unused,
XrmQuarkList quarks,
@@ -861,7 +850,7 @@
}
void
-rxvt_term::enumerate_keysym_resources (void (*cb)(rxvt_term *, const char *, const char *))
+rxvt_term::enumerate_resources (void (*cb)(rxvt_term *, const char *, const char *), const char *name_p, const char *class_p)
{
/*
* [R5 or later]: enumerate the resource database
@@ -876,25 +865,25 @@
XrmName name_prefix[3];
XrmClass class_prefix[3];
- name_prefix[1] = XrmStringToName ("keysym");
+ name_prefix[1] = name_p ? XrmStringToName (name_p) : NULLQUARK;
name_prefix[2] = NULLQUARK;
- class_prefix[1] = XrmStringToName ("Keysym");
+ class_prefix[1] = class_p ? XrmStringToName (class_p) : NULLQUARK;
class_prefix[2] = NULLQUARK;
# ifdef RESFALLBACK
name_prefix[0] = class_prefix[0] = XrmStringToName (RESFALLBACK);
/* XXX: Need to check sizeof (rxvt_t) == sizeof (XPointer) */
XrmEnumerateDatabase (database, name_prefix, class_prefix,
- XrmEnumOneLevel, rxvt_keysym_enumerate_helper, (XPointer)closure);
+ XrmEnumOneLevel, rxvt_enumerate_helper, (XPointer)closure);
# endif
name_prefix[0] = class_prefix[0] = XrmStringToName (RESCLASS);
XrmEnumerateDatabase (database, name_prefix, class_prefix,
- XrmEnumOneLevel, rxvt_keysym_enumerate_helper, (XPointer)closure);
+ XrmEnumOneLevel, rxvt_enumerate_helper, (XPointer)closure);
name_prefix[0] = class_prefix[0] = XrmStringToName (rs[Rs_name]);
XrmEnumerateDatabase (database, name_prefix, class_prefix,
- XrmEnumOneLevel, rxvt_keysym_enumerate_helper, (XPointer)closure);
+ XrmEnumOneLevel, rxvt_enumerate_helper, (XPointer)closure);
#endif
}
