Important: The information in this document is obsolete and should not be used for new development.
VInstallYou can use the
VInstallfunction to install a task record into the system-based vertical retrace queue.
FUNCTION VInstall (vblTaskPtr: QElemPtr): OSErr;
- A pointer to the task record to add to the queue.
VInstallfunction installs the VBL task record specified by the
vblTaskPtrparameter in the system-based vertical retrace queue. The Vertical Retrace Manager executes the task at intervals determined by the task record's
vblPhasefields. The task must reset the value of the task record's
vblCountfield if you want the task to be executed again.
In current versions of system software, the Vertical Retrace Manager does not continue to execute tasks installed using the
VInstallfunction when the application that installed them is switched out, unless the address in the
vblAddrfield of the task record points in the system partition.
ASSEMBLY-LANGUAGE INFORMATIONThe registers on entry and exit for
Registers on entry A0 Pointer to the task record
Registers on exit D0 Result code
noErr 0 No error vTypErr -2 Invalid
qTypevalue (must be