Inside Macintosh: Sound

Synchronizing Sound With Other Actions

If your application uses callback procedures to play sound asynchronously, you might wish to synchronize sound play with other activity, such as an onscreen animation.

Callback procedures allow your application to do that by using different constant values in the param1 field of the callback command. For example, you could define a constant kFirstSoundFinished to signal to your application that the first of a series of sounds has finished playing. Then, your callback procedure could set an appropriate global flag depending on whether the param1 field equals kFirstSoundFinished , kSoundComplete , or some other constant that your application defines. Finally, a procedure that you call once each time through your application's event loop could check to see which of the various global flag variables are set and respond appropriately. Meanwhile, sound continues to play.