-int grab_keyboard(gboolean grab);
-void grab_pointer(gboolean grab, Cursor cur);
-void grab_pointer_window(gboolean grab, Cursor cur, Window win);
+gboolean grab_keyboard(gboolean grab);
+gboolean grab_pointer(gboolean grab, Cursor cur);
+gboolean grab_pointer_window(gboolean grab, Cursor cur, Window win);