INT 21 U - OS/2 v2.1+ Virtual DOS MachineA special type of virtual machine provided by OS/2 version 2.0, in which a copy of MS-DOS or an MS-DOS compatible operating system (or even an incompatible 8086 operating system) is run and appears to have full control of the system.  See also Virtual Machine, INT 21h Function 64h. - OS/2 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. support
	AH = 64h
	CX = 636Ch ("cl")
	BX = 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. ordinal (see #01747)
	other registers as appropriate for 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. call
Return: as appropriate for 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. call
SeeAlso: AH=64h/BX=0025h,AH=64h/BX=00B6h,AH=64h/BX=00CBh


(Table 01747)
Values for OS/2 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. ordinal:
 0025h	DOS32StartSession
 0082h	DosGetCP
 00B6h	DosQFSAttach
 00BFh	DosEditName
 00CBh	DosForceDelete
 0144h	Dos32CreateEventSem
 0145h	Dos32OpenEvenSem
 0146h	Dos32CloseEventSem
 0147h	Dos32ResetEventSem
 0148h	Dos32PostEventSem
 0149h	Dos32WaitEventSem
 014Ah	Dos32QueryEventSem
 014Bh	Dos32CreateMutexSem
 014Ch	Dos32OpenMutexSem
 014Dh	Dos32CloseMutexSem
 014Eh	Dos32RequestMutexSem
 014Fh	Dos32ReleaseMutexSem
 0150h	Dos32QueryMutexSem
 0151h	Dos32CreateMuxWaitSem
 0152h	Dos32OpenMuxWaitSem
 0153h	Dos32CloseMuxWaitSem
 0154h	Dos32WaitMuxWaitSem
 0155h	Dos32AddMuxWaitSem
 0156h	Dos32DeleteMuxWaitSem
 0157h	Dos32QueryMuxWaitSem