en:docs:dpmi:api:int31:03:04

Note: This API calls are shared between DOS and Win16 personality.

DOSX is a specialized version of DPMI. Windows standard and extended mode kernel is a DPMI client app. Standard and extended mode kernel differs minimally and shares common codebase. Standard mode is just DPMI client, exnhanced mode is DPMI client running under Virtual Machime Manager. 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 provides Version 1.0 DPMI support, but reported as 0.9.

2021/08/05 12:15 · prokushev

Int 31H, AH=03H, AL=04H

Version

0.9

Brief

Free Real Mode Callback Address

Input

AX = 0304H
CX:DX = real mode callback address to be freed

Return

if function successful
Carry flag = clear

if function unsuccessful
Carry flag = set
AX = error code
8024H	invalid callback address

Notes

Releases a real mode callback address that was previously allocated with the Allocate Real Mode Callback Address function (Int 31H Function 0303H).

Real mode callbacks are a limited system resource. A client should release any callback that it is no longer using.

See also

Note

DPMI
Process manager INT 2FH 1680H, 1687H
Signals
Memory manager
Misc INT 2FH 1686H, 168AH
Devices
2021/08/13 16:23 · prokushev

en/docs/dpmi/api/int31/03/04.txt · Last modified: 2021/08/27 05:49 by prokushev