DOSMGR_End_V86_App

include vmm.inc
include dosmgr.inc

; Install a hook procedure

GetVxDServiceOrdinal eax, DOSMGR_End_V86_App
mov esi, OFFSET32 HookProc
VMMcall Hook_Device_Service

jc error
 

This service is called internally by DOSMGR when a V86-mode application has ended execution. VxDs which wish to be notified of this activity must hook this service. VxDs must not call this service directly. The hook procedure must be a 4.0 Hook_Proc style procedure.

VxDs which monitor resources may wish to hook this service (and the corresponding DOSMGR_Begin_V86_App) in order to allocate and free resources for each MS-DOS-based application. To monitor Windows-based applications, VxDs should monitor the system control calls related to threads.

The system calls the hook procedure as follows:

mov ebx, VMHandle
mov esi, HighLinearPSP
mov dx,  AppPSP
mov cx, AppExitCode
 

VMHandle

VM that performed the int 21.

HighLinearPSP

High linear address of the program segment prefix (PSP) which is terminating.

AppPSP

Segment value of the PSP of the application which is terminating.

AppExitCode

Application exit code. This is the value which will be returned in AX when the parent calls Get Child-Program Return Value (Interrupt 21h function 4Dh).

CH	Application exit type
CH = 0	Normal termination
CH = 1	Terminated via Ctrl+C
CH = 2	Terminated due to critical error (e.g., disk I/O error)
CH = 3	Terminated and stayed resident
CL	Application return code (application-specific value)

Any VxD which hooks the service must pass the call down to the previously-installed hook, preserving all registers, (except Flags) even registers reserved for future use.

Do not assume that the high bytes of the EDX and ECX registers will be zero.