[glib] g_atomic_int_add: document that the return value is new

[Simon McVittie <smcv src gnome org>]

commit b34eac204f54cefaf8a702a96dc537144f8c2d92
Author: Simon McVittie <simon mcvittie collabora co uk>
Date:   Thu Jul 21 10:22:01 2011 +0100

    g_atomic_int_add: document that the return value is new
    
    Bug: https://bugzilla.gnome.org/show_bug.cgi?id=654988
    Reviewed-by: Matthias Clasen <mclasen redhat com>

 glib/gatomic.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/glib/gatomic.c b/glib/gatomic.c
index 495d090..328ad4f 100644
--- a/glib/gatomic.c
+++ b/glib/gatomic.c
@@ -206,6 +206,9 @@ gboolean
  *
  * This call acts as a full compiler and hardware memory barrier.
  *
+ * Before version 2.30, this function did not return a value
+ * (but g_atomic_int_exchange_and_add() did, and had the same meaning).
+ *
  * Returns: the value of @atomic before the add, signed
  *
  * Since: 2.4