Getting the Current Callback Function

Before inserting a callback function into the playback, you should determine whether another function is already attached. If a callback function does exist, you should call it from your callback function. Using this chaining technique, your application can hook multiple functions into the playback.

To get the procedure-instance address of the most recently attached callback function, call mmpGetFrameHook. This function returns a pointer to the current callback function and has the following syntax:

FARPROC mmpGetFrameHook(idMovie)

Pass the movie ID of the Movie Player instance to idMovie. If no callback function is attached, mmpGetFrameHook returns NULL.