Using the Callback Functions(IM: QC)

Inside Macintosh: QuickTime Components /

Chapter 11 - Clock Components / Clock Components Reference

Using the Callback Functions
Applications that use QuickTime time bases may define callback functions that are associated with a specific time base. Applications can then use these callback functions to perform activities that are triggered by temporal events, such as a certain time being reached or a specified rate being achieved. The time base functions of the Movie Toolbox interact with clock components to schedule the invocation of these callback
functions--your clock component is responsible for calling the callback function at its scheduled time.
The functions described in this section are called by the Movie Toolbox to support applications that define time base callback functions. For more information about time base callback functions, see the chapter "Movie Toolbox" in Inside Macintosh: QuickTime. Note that your clock component can delegate its callback events to another component by calling the Component Manager's DelegateComponent function, which is described in the chapter "Component Manager" in Inside Macintosh: More Macintosh Toolbox.
The ClockNewCallBack function allows your clock component to allocate the memory to support a new callback event. When an application discards a callback event, the Movie Toolbox calls your clock component's ClockDisposeCallBack function.
The Movie Toolbox calls your clock component's ClockCallMeWhen function when an application wants to schedule a callback event. When the callback function is to be invoked to service the event, the Movie Toolbox calls your component's ClockCancelCallBack function so that you can remove the callback event from the list of scheduled events.

Subtopics

ClockNewCallBack

ClockCallMeWhen

ClockCancelCallBack

ClockDisposeCallBack