Errorlevel

 BBS: Inland Empire Archive
Date: 12-08-92 (13:13)             Number: 350
From: ROB MCKEE                    Refer#: NONE
  To: ALL                           Recvd: NO  
Subj: Errorlevel                     Conf: (2) Quik_Bas

Hi All,
      I found out where MS-Dos V.5 Command.com keeps the
ErrorLevel Info (plus &h2b3 from the beginning of
Command.com as Listed by Mem /d)  Does anyone know

C:\>MEM/D

  Address     Name          Size       Type
  -------     --------     ------     ------
  000000                   000400     Interrupt Vector
  000400                   000100     ROM Communication Area
  000500                   000200     DOS Communication Area

  000700      IO           000A60     System Data
                  CON                   System Device Driver
  _____________________/\  ____________________________
                         \/
                  COM4                  System Device Driver

  001160      MSDOS        0013D0     System Data

  002530      IO           002C70     System Data
  _____________________/\  ____________________________
                         \/
  0051B0      MSDOS        000040     System Program

  005200      COMMAND      000940     Program
  005B50      EZPOINT      000040     Data
  005BA0      COMMAND      000400     Environment

 The byte on my computer as configured is 0054B3.  But what
I want to know how to do is access the List of List from
within QBas.  I wrote an ASM program thats hardcoded to
read the Byte at &h54b3.  I would like to be able to find
where COMMAND.COM start's in any computer and then read the
ERRORLEVEL.

 n ErrLvl.com
 RCX
 4b
 a
   MOV AX,054B                   ; Point to Segment
   PUSH    DS                    ; Save Data Seg
   MOV DS,AX                     ; Load new Data Segment
   MOV AL,[0003]                 ; Get Errorlevel
   POP DS                        ; Restore Data Segment
   JMP 0113                      ; Jmp around Data
   DB 00 00 00 0D 0A 24 00       ; Working Data
   MOV [0112],AL                 ; Save Errorlevel
   CMP AL,00                     ; Is it 0 don't need to Divide then
   JZ  012F                      ; If 0 skip Divide
   XOR AH,AH                     ; 0 out Remainder
   MOV BL,0A                     ; Set Divisor
   DIV BL                        ; Divide
   MOV [010E],AH                 ; Save the 1's digit
   XOR AH,AH                     ; 0 out Remainder
   DIV BL                        ; Divide
   MOV [010D],AH                 ; Save the 10's digit
   MOV [010C],AL                 ; Save the 100's digit
   MOV DX,010C                   ; Set start of string
   MOV AH,09                     ; Load for Output String Func
   ADD BYTE PTR [010C],30        ; Add 30h to make it Ascii #
   ADD BYTE PTR [010D],30        ; Add 30h to make it Ascii #
   ADD BYTE PTR [010E],30        ; Add 30h to make it Ascii #
   INT 21                        ; Output the String
   MOV AL,[0112]                 ; Get the ERRORLEVEL again
   MOV AH,4C                     ; Setup for Exit with ERRORLEVEL
   INT 21                        ; ByeBye...

   w
   q
 ------------------------------ 8< ---------------------------
 AS you can see, it Exit's with the same Errorlevel that it
had coming into it.  I have a listing of the Dos 3.x Master
List but I don't know if it's the same as Dos 5.  If I can
intercept the ErrorLevel inside Qbas then I can replace
alot of 'IF ERRORLEVEL statements in my Bat Files and do
more things in my Bat files.

                               TTYL -Rob

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                               TTYL -Rob