From e96f66d8817d89c51b5066ed0cd69fcda8620306 Mon Sep 17 00:00:00 2001
From: Richard Carlsson <richardc@klarna.com>
Date: Wed, 9 Jan 2019 14:14:58 +0100
Subject: Document that current_function can be undefined

If a process is executing in native-compiled code, process_info(Pid,
current_function) may return the atom undefined instead of an MFA.
---
 erts/doc/src/erlang.xml | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

(limited to 'erts/doc/src/erlang.xml')

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 8e014c3010..ab9aadcc54 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -5182,11 +5182,13 @@ RealSystem = system + MissedSystem</code>
               changed or removed without prior notice.</p>
           </item>
           <tag><c>{current_function, {<anno>Module</anno>,
-            <anno>Function</anno>, Arity}}</c></tag>
+            <anno>Function</anno>, Arity} | undefined}</c></tag>
           <item>
             <p><c><anno>Module</anno></c>, <c><anno>Function</anno></c>,
               <c><anno>Arity</anno></c> is
-              the current function call of the process.</p>
+              the current function call of the process. The value
+              <c>undefined</c> can be returned if the process is
+              currently executing native compiled code.</p>
           </item>
           <tag><c>{current_location, {<anno>Module</anno>,
             <anno>Function</anno>, <anno>Arity</anno>,
-- 
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