gmain: Do atomic addition before checking the old value on ref

So we avoid working on a value that is not been updated yet.

1 files changed, 4 insertions, 2 deletions

diff --git a/glib/gmain.c b/glib/gmain.c
index a0ade8acb..6571fa239 100644
--- a/glib/gmain.c
+++ b/glib/gmain.c
@@ -551,10 +551,12 @@ GSourceFuncs g_idle_funcs =
 GMainContext *
 g_main_context_ref (GMainContext *context)
 {
+  int old_ref_count;
+
   g_return_val_if_fail (context != NULL, NULL);
-  g_return_val_if_fail (g_atomic_int_get (&context->ref_count) > 0, NULL); 
 
-  g_atomic_int_inc (&context->ref_count);
+  old_ref_count = g_atomic_int_add (&context->ref_count, 1);
+  g_return_val_if_fail (old_ref_count > 0, NULL);
 
   return context;
 }