diff --git a/legacy/elementary/src/lib/Elementary.h.in b/legacy/elementary/src/lib/Elementary.h.in
index 04e65f46f2..413cb7c5d6 100644
--- a/legacy/elementary/src/lib/Elementary.h.in
+++ b/legacy/elementary/src/lib/Elementary.h.in
@@ -16684,7 +16684,7 @@ extern "C" {
     * By default, a toolbar will be horizontal. Use this function to determine whether a toolbar is vertical.
     * @ingroup Toolbar
     */
-   EAPI Eina_Bool elm_toolbar_horizontal_get(const Evas_Object *obj);
+   EAPI Eina_Bool elm_toolbar_horizontal_get(const Evas_Object *obj) EINA_ARG_NONNULL(1);
 
    /**
     * Get the number of items in a toolbar