File 1040-erlang-module-doc-is_process_alive.patch of Package erlang

From e1bd0f040b31a64529c34626a948cd0797cb39dc Mon Sep 17 00:00:00 2001
From: Kjell Winblad <kjellwinblad@gmail.com>
Date: Tue, 22 Sep 2020 15:05:19 +0200
Subject: [PATCH 30/39] erlang module doc: is_process_alive

* Add example
* Add info about order guarantee
---
 erts/doc/src/erlang.xml | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index a16c12e034..a935130658 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -2818,7 +2818,27 @@ false</code>
           node.</p>
         <p>Returns <c>true</c> if the process exists and is alive, that
           is, is not exiting and has not exited. Otherwise returns
-          <c>false</c>.</p>
+        <c>false</c>.</p>
+        <p>If process <c>P1</c> calls <c>is_process_alive(P2Pid)</c>
+        it is guaranteed that all signals, sent from <c>P1</c> to
+        <c>P2</c> (<c>P2</c> is the process with identifier
+        <c>P2Pid</c>) before the call, will be delivered to <c>P2</c>
+        before the aliveness of <c>P2</c> is checked. This guarantee
+        means that one can use <c>is_process_alive/1</c> to let a
+        process <c>P1</c> wait until a process <c>P2</c>, which has
+        got an exit signal with reason <c>kill</c> from P1, is
+        killed. Example:
+        </p>
+<pre>
+exit(P2Pid, kill),
+% P2 might not be killed
+is_process_alive(P2Pid),
+% P2 is not alive (the call above always return false)
+</pre>
+       <p>See the documentation about <seealso
+       marker="erts:communication">communication in Erlang</seealso>
+       and <seealso marker="#exit/2">erlang:exit/2</seealso> for more
+       information about signals and exit singnals.</p>
       </desc>
     </func>
 
-- 
2.26.2