Specifications

CHAPTER 4
Software Support
Control and Status Calls 63
keyboard, the driver monitors the keyboard input data for the deactivate key
combination and calls the user-defined task when that key combination occurs.
The status code for this routine is rsDeactivateKey = 104.
The user-defined task is called during NeedTime, which is the period after the
deactivate key and modifiers are pressed. (If a driver has the dNeedTime flag set, it gets
called in round-robin fashion at System Task time.)
If the user-defined task is null, no task is called. The modifiers are specified as they
appear in KeyMap+6. The value of the deactivate key is the Macintosh key code of the
desired key. KeyMap refers to the variable type referred to by the GetKeys call. This is
documented in Inside Macintosh: Macintosh Toolbox Essentials, Chapter 2, “Event
Manager.”
Parameter block
—> indicates input to the driver
<— indicates output from the driver
Upon return, the parameter block is set as follows.
Control and Status Calls 4
An application running on the Mac OS can use the interface driver to make control and
status calls to the PC system. You can use the routines in this section to do the following:
■ get the status of the PC system
■ enable and disable the PC system’s video display
■ enable and disable disk mounting on the PC system
■ activate and deactivate keyboard operation by the PC system
■ activate and deactivate mouse tracking by the PC system
—> ioCompletion long Pointer to the completion routine.
<— ioResult word Device driver’s result code.
—> ioRefNum word Device driver’s reference number.
—> csCode word Equals rsSetDeactivateKey.
—> csParam+0 long Pointer to user-defined task.
—> csParam+4 word Modifiers.
—> csParam+6 word The deactivate key.
<— csParam+0 long Pointer to the previous user-defined task.
<— csParam+4 word The previous modifiers.
<— csParam+6 word The previous deactivate key.