File coreutils-8.4-tail-sleepinterval.patch of Package timeout

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File coreutils-8.4-tail-sleepinterval.patch of Package timeout

diff -urNp coreutils-8.4-orig/doc/coreutils.texi coreutils-8.4/doc/coreutils.texi
--- coreutils-8.4-orig/doc/coreutils.texi	2011-08-08 12:46:29.302542993 +0200
+++ coreutils-8.4/doc/coreutils.texi	2011-08-08 13:06:38.638528977 +0200
@@ -2797,6 +2797,18 @@ no @var{file} operand is specified and s
 Likewise, the @option{-f} option has no effect for any
 operand specified as @samp{-}, when standard input is a FIFO or a pipe.
 
+With kernel inotify support, output is triggered by file changes
+and is generally very prompt.
+Otherwise, @command{tail} sleeps for one second between checks---
+use @option{--sleep-interval=@var{number}} to change that default---which can
+make the output appear slightly less responsive or bursty.
+When using tail without inotify support, you can make it more responsive
+by using a sub-second sleep interval, e.g., via an alias like this:
+
+@example
+alias tail='tail -s.1'
+@end example
+
 @item -F
 @opindex -F
 This option is the same as @option{--follow=name --retry}.  That is, tail
@@ -2820,6 +2832,10 @@ Historical implementations of @command{t
 @var{number} be an integer.  However, GNU @command{tail} accepts
 an arbitrary floating point number (using a period before any
 fractional digits).
+When @command{tail} uses inotify, this polling-related option
+is usually ignored. However, if you also specify @option{--pid=@var{p}},
+@command{tail} checks whether process @var{p} is alive at least
+every @var{number} seconds.
 
 @itemx --pid=@var{pid}
 @opindex --pid
@@ -2854,7 +2870,8 @@ still associated with the same device/in
 When following a log file that is rotated, this is approximately the
 number of seconds between when tail prints the last pre-rotation lines
 and when it prints the lines that have accumulated in the new log file.
-This option is meaningful only when following by name.
+This option is meaningful only when polling (i.e., without inotify)
+and when following by name.
 
 @itemx -n @var{k}
 @itemx --lines=@var{k}
diff -urNp coreutils-8.4-orig/src/tail.c coreutils-8.4/src/tail.c
--- coreutils-8.4-orig/src/tail.c	2010-01-03 18:06:20.000000000 +0100
+++ coreutils-8.4/src/tail.c	2011-08-08 13:00:44.232529702 +0200
@@ -284,7 +284,8 @@ Mandatory arguments to long options are 
                            with --follow=name, reopen a FILE which has not\n\
                            changed size after N (default %d) iterations\n\
                            to see if it has been unlinked or renamed\n\
-                           (this is the usual case of rotated log files)\n\
+                           (this is the usual case of rotated log files).\n\
+                           With inotify, this option is rarely useful.\n\
 "),
              DEFAULT_N_LINES,
              DEFAULT_MAX_N_UNCHANGED_STATS_BETWEEN_OPENS
@@ -298,7 +299,9 @@ Mandatory arguments to long options are 
 "), stdout);
      fputs (_("\
   -s, --sleep-interval=N   with -f, sleep for approximately N seconds\n\
-                             (default 1.0) between iterations\n\
+                             (default 1.0) between iterations.\n\
+                           With inotify and --pid=P, check process P at\n\
+                           least once every N seconds.\n\
   -v, --verbose            always output headers giving file names\n\
 "), stdout);
      fputs (HELP_OPTION_DESCRIPTION, stdout);
@@ -1391,9 +1394,10 @@ tail_forever_inotify (int wd, struct Fil
   evlen += sizeof (struct inotify_event) + 1;
   evbuf = xmalloc (evlen);
 
-  /* Wait for inotify events and handle them.  Events on directories make sure
-     that watched files can be re-added when -F is used.
-     This loop sleeps on the `safe_read' call until a new event is notified.  */
+/* Wait for inotify events and handle them. Events on directories
+ ensure that watched files can be re-added when following by name.
+ This loop blocks on the `safe_read' call until a new event is notified.
+ But when --pid=P is specified, tail usually waits via the select. */
   while (1)
     {
       struct File_spec *fspec;

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File coreutils-8.4-tail-sleepinterval.patch of Package timeout

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