INT 21 U - PCIBM PC Tools v7+ VDEFEND, VSAFE, VWATCH - API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running. Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. AH = FAh DX = 5945h AL = function (00h-02h for VDEFEND, 00h-07h for VSAFE and VWATCH) Return: varies by function Note: this API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running. Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. is identical to the API(Application Program[ming] Interface) The defined set of calls which a program may make to interact with or request services of the operating system or environment under which it is running. Because the inputs and outputs of the calls are well-defined, a program using the API can continue using the identical calls even if the internal organization of the program providing the API changes. on INT 13/AH=FAh and INT 16/AH=FAh, so it is listed in its entirety only under INT 16/AX=FA00h and following SeeAlso: INT 13/AX=FA00h,INT 16/AX=FA00h