From: Tom Tromey <tromey@redhat.com>
Date: Tue, 27 Aug 2013 18:29:05 +0000 (-0600)
Subject: add a comment before flush_stack_call_func
X-Git-Tag: emacs-26.0.90~1144^2~17^2~15
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=5b05b5a6bc5a3293e692d9db969e8a24aa80f1a6;p=emacs.git

add a comment before flush_stack_call_func
---

diff --git a/src/alloc.c b/src/alloc.c
index 9b5f2955aa5..5de7d384a49 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -4704,6 +4704,17 @@ mark_stack (char *bottom, char *end)
 #endif
 }
 
+/* This is a trampoline function that flushes registers to the stack,
+   and then calls FUNC.  ARG is passed through to FUNC verbatim.
+
+   This function must be called whenever Emacs is about to release the
+   global interpreter lock.  This lets the garbage collector easily
+   find roots in registers on threads that are not actively running
+   Lisp.
+   
+   It is invalid to run any Lisp code or to allocate any GC memory
+   from FUNC.  */
+
 void
 flush_stack_call_func (void (*func) (void *arg), void *arg)
 {