diff --git a/awesome.c b/awesome.c
index 5511d2b67..b23261f67 100644
--- a/awesome.c
+++ b/awesome.c
@@ -73,6 +73,7 @@ scan()
             real_screen = screen;
             for(i = 0; i < num; i++)
             {
+                /* XGetWindowAttributes return 1 on success */
                 if(!XGetWindowAttributes(globalconf.display, wins[i], &wa)
                    || wa.override_redirect
                    || XGetTransientForHint(globalconf.display, wins[i], &d1))