Note: This API calls are shared between DOS and Win16 personality.
DPMI is a shared interface for DOS applications to access Intel 80286+ CPUs services. DOS DMPI host provides core services for protected mode applications. Multitasking OS with DOS support also provides DMPI in most cases. Windows standard and extended mode kernel is a DPMI client app. Standard and extended mode kernel differs minimally and shares common codebase. Standard Windows kernel works under DOSX extender. DOSX is a specialized version of 16-bit DPMI Extender (but it is standard DPMI host). Standard mode is just DPMI client, exnhanced mode is DPMI client running under Virtual Machime Manager (really, multitasker which allow to run many DOS sessions). Both modes shares DPMI interface for kernel communication. The OS/2 virtual DOS Protected Mode Interface (VDPMI) device driver provides Version 0.9 DPMI support for virtual DOS machines. Win16 (up to Windows ME) provides Version 0.9 DPMI support. Windows in Standard Mode provides DPMI services only for Windows Applications, not DOS sessions.
DPMI host often merged with DPMI extender. Usually DPMI extender provide DPMI host standard services and DOS translation or True DPMI services.
Int 31H, AH=0AH, AL=00H
Version
0.9
Brief
Get Vendor-Specific API Entry Point
Input
AX = 0A00H DS:(E)SI = selector:offset of ASCIIZ (null-terminated) string which identifies the DPMI host vendor
Return
if function successful Carry flag = clear ES:(E)DI = selector:offset of extended API entry point and DS, FS, GS, EAX, EBX, ECX, EDX, ESI, and EBP may be modified. if function unsuccessful Carry flag = set AX = error code 8001H unsupported function (extension not found)
Notes
Returns an address which can be called to use host-specific extensions to the standard set of DPMI functions. DPMI 1.0 clients should avoid use of this function.
The null-terminated string specifies the host-specific vendor name or some other unique identifier to obtain a specific extension entry point. The string comparison used to look up the API entry point is case-sensitive.
Clients must use a FAR CALL to reach the extended API entry point.
All extended API parameters are specified by the vendor.
DPMI 1.0 clients should use Int 2FH Function 168AH in preference to this function. DPMI 1.0 hosts support this function solely for backward compatibility with DPMI 0.9 clients.
See also
Note
Text based on http://www.delorie.com/djgpp/doc/dpmi/