garbage-collect doc string clarification

* src/alloc.c (Fgarbage_collect): Mention that calling this
function is not guaranteed to collect all the garbage (bug#34404).

diff --git a/src/alloc.c b/src/alloc.c
index 504ef179eccec570de71e695c24c61595c6f02b8..34f822e589e17c321e217aa85abc2146b481e8cd 100644 (file)
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -6154,10 +6154,17 @@ where each entry has the form (NAME SIZE USED FREE), where:
 - FREE is the number of those objects that are not live but that Emacs
   keeps around for future allocations (maybe because it does not know how
   to return them to the OS).
+
 However, if there was overflow in pure space, and Emacs was dumped
 using the 'unexec' method, `garbage-collect' returns nil, because
 real GC can't be done.
-See Info node `(elisp)Garbage Collection'.  */)
+
+Note that calling this function does not guarantee that absolutely all
+unreachable objects will be garbage-collected.  Emacs uses a
+mark-and-sweep garbage collector, but is conservative when it comes to
+collecting objects in some circumstances.
+
+For further details, see Info node `(elisp)Garbage Collection'.  */)
   (void)
 {
   if (garbage_collection_inhibited)