Legacy Document

Inside Macintosh: Processes

Chapter 4 - Vertical Retrace Manager / Vertical Retrace Manager Reference

Vertical Retrace Manager Routines / Slot-Based Installation and Removal Routines

SlotVInstall

You can use the SlotVInstall function to install a task record in a slot-based vertical retrace queue.

FUNCTION SlotVInstall (vblTaskPtr: QElemPtr; theSlot: Integer):
                         OSErr;

vblTaskPtr

A pointer to the task record to add to a queue.

theSlot

The slot number of the video device to whose vertical retrace queue the task record is added.

DESCRIPTION

The SlotVInstall function installs the task record specified by the vblTaskPtr parameter in the vertical retrace queue associated with the video device specified by the theSlot parameter. The Vertical Retrace Manager executes the task at intervals determined by the task record's vblCount and vblPhase fields. The task must reset the value of the task record's vblCount field if you want the task to be executed again.

The Vertical Retrace Manager continues to execute tasks installed using the SlotVInstall function even when the application that installed them is switched out.

ASSEMBLY-LANGUAGE INFORMATION

The registers on entry and exit for SlotVInstall are

Registers on entry
A0	Pointer to the task record
D0	Slot number of the device associated with the vertical retrace queue

Registers on exit
D0	Result code

RESULT CODES

noErr	0	No error
vTypErr	-2	Invalid qType value (must be ORD(vType))
slotNumErr	-360	Invalid slot number