{
freeglut_assert_ready;
freeglut_return_if_fail( fgStructure.Window != NULL );
- freeglut_return_if_fail( fgStructure.Window->Callbacks.Joystick != NULL );
+ freeglut_return_if_fail( FETCH_WCB( *( fgStructure.Window ), Joystick ) );
fgJoystickPollWindow( fgStructure.Window );
}