The WM_CPL_LAUNCHED message is sent when a Control Panel application, started by the WM_CPL_LAUNCH message, has closed. The WM_CPL_LAUNCHED message is sent to the window identified by the wParam parameter of the WM_CPL_LAUNCH message that started the application.
WM_CPL_LAUNCHED fAppStarted = (BOOL) wParam;
The value returned by the application is ignored for this message.