diff --git a/unix/gtkwin.c b/unix/gtkwin.c
index 9a3f91f1..290a851f 100644
--- a/unix/gtkwin.c
+++ b/unix/gtkwin.c
@@ -1497,8 +1497,6 @@ static void inst_post_main(struct gui_data *inst)
          * when we get out of the next one. */
         request_post_main(inst);
     }
-
-    return 0;
 }
 
 static gint idle_toplevel_callback_func(gpointer data)