File 0320-erlang-module-doc-preciser-description-of-erlang-yie.patch of Package erlang

From a01ec2f8bb07dd566b95bf845a916a111c661d64 Mon Sep 17 00:00:00 2001
From: Kjell Winblad <kjellwinblad@gmail.com>
Date: Thu, 17 Sep 2020 11:40:26 +0200
Subject: [PATCH 20/39] erlang module doc: preciser description of
 erlang:yield()

---
 erts/doc/src/erlang.xml       | 22 ++++++++++++++--------
 erts/preloaded/src/erlang.erl |  2 ++
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 45b37db10d..2e8c9f5247 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -12155,16 +12155,22 @@ true</pre>
       <name name="yield" arity="0" since=""/>
       <fsummary>Let other processes get a chance to execute.</fsummary>
       <desc>
-        <p>Voluntarily lets other processes (if any) get a chance to
-          execute. Using this function is similar to
-          <c>receive after 1 -> true end</c>, except that <c>yield()</c>
-          is faster.</p>
+        <p>Tries to give other processes with the same or
+        higher priority (if any) a chance to execute before
+        returning. There is no guarantee that any other process runs
+        between the invocation and return of <c>erlang:yield/0</c>.</p>
+
+        <p>See the documentation for <seeguide
+        marker="system/reference_manual:expressions#receive"><c>receive-after</c>
+        expressions</seeguide> for how to make the current process
+        sleep for a specific number of milliseconds.</p>
         <warning>
-          <p>There is seldom or never any need to use this BIF
-            as other processes have a chance to run in another scheduler
-            thread anyway.
+          <p>There is seldom or never any need to use this BIF.
             Using this BIF without a thorough grasp of how the scheduler
-            works can cause performance degradation.</p>
+            works can cause performance degradation. The current implementation
+            of this function puts the current process last in the current
+            scheduler's queue for processes of the same priority as the
+            current process.</p>
         </warning>
       </desc>
     </func>
diff --git a/erts/preloaded/src/erlang.erl b/erts/preloaded/src/erlang.erl
index 700b84bf25..60caad2b1e 100644
--- a/erts/preloaded/src/erlang.erl
+++ b/erts/preloaded/src/erlang.erl
@@ -3335,6 +3335,8 @@ spawn_request_abandon(_ReqId) ->
 
 -spec erlang:yield() -> 'true'.
 yield() ->
+    % This is not an infinite loop because erlang:yield() is
+    % translated to an instruction by the loader
     erlang:yield().
 
 -spec nodes() -> Nodes when
-- 
2.26.2