Inside Macintosh: QuickTime /

Chapter 2 - Movie Toolbox / Movie Toolbox Reference

Time Base Functions / Time Base Callback Functions

GetCallBackType

You can retrieve a callback event's type by calling the GetCallBackType function. You specify the type value when you call the NewCallBack function (described on page 2-317).

pascal short GetCallBackType (QTCallBack cb);

cb

Specifies the callback event for the operation. You obtain this value from the NewCallBack function.

DESCRIPTION

The GetCallBackTimeBase function returns the callback event's type value. The following values are valid:

callBackAtTime

Indicates that the event is to be invoked at a specified time.

callBackAtRate

Indicates that the event is to be invoked when the rate for the time base reaches a specified value.

callBackAtTimeJump

Indicates that the event is to be invoked when the time base's time value changes by an amount that differs from its rate.

In addition, if the high-order bit of the returned value is set to 1 (this bit is defined by the callBackAtInterrupt flag), the event can be invoked at interrupt time.

ERROR CODES

None