en:docs:dos:api:int21:4d

Note: This API call is for DOS personality only. Use Family API for portability.

2018/09/07 07:04 · prokushev

Int 21H, AH=4DH

Version

2 and higher

Brief

GET RETURN CODE (ERRORLEVEL)

Family API

Input

AH = 4Dh

Return

 AH = termination type
    00h normal (INT 20,INT 21/AH=00h, or INT 21/AH=4Ch)
    01h control-C abort
    02h critical error abort
    03h terminate and stay resident (INT 21/AH=31h or INT 27)
AL = return code
CF clear

Notes

the word in which DOS stores the return code is cleared after being
  read by this function, so the return code can only be retrieved once
COMMAND.COM stores the return code of the last external command it
  executed as ERRORLEVEL
this call should not be used if the child was started with AX=4B04h;
  use AH=8Ah instead
the following sequence will close a Virtual DOS Machine under OS/2 2.0
  through OS/2 Merlin (but may change in the future):
    MOV	AH,4Dh
    INT	21h
    HLT
    DB	02h,0FDh
  This sequence is the only way to close a specific VDM which was
  booted from floppy or a disk image.
        

See also

AH=4Bh,AH=4Ch,AH=8Ah

Note


en/docs/dos/api/int21/4d.txt · Last modified: 2021/05/02 06:56 by prokushev