Important: The information in this document is obsolete and should not be used for new development.
VInstall
You can use theVInstall
function to install a task record into the system-based vertical retrace queue.
FUNCTION VInstall (vblTaskPtr: QElemPtr): OSErr;
vblTaskPtr
- A pointer to the task record to add to the queue.
DESCRIPTION
TheVInstall
function installs the VBL task record specified by thevblTaskPtr
parameter in the system-based vertical retrace queue. The Vertical Retrace Manager executes the task at intervals determined by the task record'svblCount
andvblPhase
fields. The task must reset the value of the task record'svblCount
field 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
VInstall
function when the application that installed them is switched out, unless the address in thevblAddr
field of the task record points in the system partition.ASSEMBLY-LANGUAGE INFORMATION
The registers on entry and exit forVInstall
are
Registers on entry A0 Pointer to the task record
Registers on exit D0 Result code RESULT CODES
noErr 0 No error vTypErr -2 Invalid qType
value (must beORD(vType)
)