3.1.3 Extended-Function Dispatch Table

A display grabber also includes several extended functions. Windows calls the extended functions by supplying an extended-function number in the AX register when it calls the standard function InquireGrab. The InquireGrab function uses the extended-function dispatch table, consisting of function offsets, to transfer control to the desired function. This table differs from the standard-function dispatch table because it contains offsets, not jump instructions.

The extended-function dispatch table has the following form:

ExtFuncTable label word

dw Obsolete ;function 0FFF4h

dw Obsolete ;function 0FFF5h

dw Obsolete ;function 0FFF6h

dw Obsolete ;function 0FFF7h

dw GetBlock ;function 0FFF8h

dw Obsolete ;function 0FFF9h

dw GetVersion ;function 0FFFAh

dw DisableSave ;function 0FFFBh

dw EnableSave ;function 0FFFCh

dw SetSwapDrive ;function 0FFFDh

dw GetInfo ;function 0FFFEh

dw Obsolete ;function 0FFFFh