Int 7E/AX=00F7h

AX = 00F7h

Return:
AX = status
0000h failed
0001h successful
BX = ??? (if nonzero, ??? is hooked) (see AX=00FFh)
CH = ???
CL = ???

See Also: AX=00F6h - AX=00FDh - AX=00FFh