Getting the return value from a shelled EXE

[Mark Downs]

In my DOS program, I am shelling to an EXE that calls a DLL.
The EXE returns a 0 or 1.

Currently, I am doing this (with line numbers):

10 SHELL "<program> <params>"
12 IF ERRORLEVEL = 0 THEN GOTO 29000

, but it does not work.

What is the proper way to check the return value in the DOS
program?

Thanks in advance.

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[Michael Mattias]

' EXECDOS.BAS
' Execute an exteernal program as a child proccess, interrogate
' it's return code.
' For PB/DOS 3.2
' Author: Michael Mattias Racine WI 
' from original version for Microsoft QuickBASIC by Ethan Winer.


'============================================================
'     SUB TO Execute a program as a child process           
' Function value = return code of process; if < 0, error is 
' -1 * (dos error)
'============================================================

' REG equates as expected in REGS.INC
DEFINT A-Z
FUNCTION DosExecute% (Program$, Parameter$) LOCAL
  '---- Prepare the program name and parameter strings for processing.  DOS
  '     requires that the parameter string hold the length of the parameter
  '     text, followed by the parameter text, and then followed by a CHR$(13)
  '     Enter byte.  The parameter block holds two CHR$(0) bytes followed by
  '     the address and segment of the parameter string.
  '
  DIM Block   AS LOCAL STRING * 14    'this is the DOS parameter block
  DIM Parm    AS LOCAL STRING * 80    'and this is the actual parameter text

  DIM ZBuffer AS LOCAL STRING * 80    'this holds a copy of the program name

  SaveDefSeg = pbvDefSeg
  DEF SEG
  DefaultDS = pbvDefSeg
  Zero$ = CHR$(0)                  'invoke CHR$() only once for efficiency
  DOS = &H21                       'saves a few bytes
  ZBuffer$ = Program$ + Zero$      'make an ASCIIZ string for DOS

  LSET Parm$ = CHR$(LEN(Parameter$)) + Parameter$ + CHR$(13)
  LSET Block$ = Zero$ + Zero$ + MKI$(VARPTR(Parm$)) + MKI$(VARSEG(Parm$))

  Dummy& = SETMEM(-500000)         'free up memory for the program being run
  REG %RegAX, &h4B00
  REG %RegDX, VARPTR (ZBuffer$)
  REG %RegES, VARSEG(Block$)
  REG %RegBX, VARPTR(Block$) 
  REG %RegDS, DefaultDS
  CALL INTERRUPT DOS
  Flags = REG(0)
  ReturnAX = REG(%RegAX)
  IF (Flags AND 1) THEN          'DOS error trying to run the program?
    DosExecute% = -(ReturnAX)    'yes, set function value to -1 * error code
    GOTO Execute.Done            'and jump to reclaim memory
  END IF

  REG %RegAX, &H4D00               'retrieve subordinate process code
  CALL Interrupt DOS
  DosExecute% = REG (%RegAX)          'set function value to exit code

Execute.Done:
  Dummy& = SETMEM(500000)          'reclaim the memory relinquished eariler
  DEF SEG = SaveDefSeg             ' restore DS to what it was at entry.

END FUNCTION

[Michael Mattias]

No, I do not have a clue if this works calling a Windows program from a DOS application.

But I'm sure you will tell us what happened.

MCM

[Clay Clear]

A DOS program can get the exit code from a CONSOLE app - it cannot from
a GUI app.


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[Michael Mattias]

>a dos program can get the exit code from a console app - it cannot from a gui app.

hmm, then maybe my little workaround for the pb/dll 6.x/cc2.x exit code "issue" can actually be of some use...?

cc3/win7 exit code bug workaround october 26, 2002

i'll bet it wasn't four weeks after i posted this that a new release of pb came out with this bug fixed, rendering above moot.

but... you could still shell the program from a dos program, which would shell the gui program, which would return a code to the cc program, which returns the code to the dos program....

(hell, nobody asked for 'elegant' did they?)

mcm



[this message has been edited by michael mattias (edited february 02, 2004).]

[Mike Luther]

Clay ..

Why can't you run the console app as a part of a batch file? Will
it collapse into the batch file and yield any results that way? I
really don't know the answer to this question, but wanted to ask.

I know that in OS/2 you can run either a command line instance app or
a PM app with various versions of utility programs that do this that
can be used in a batch file. That means DOS-VDM's or even PM OS/2
applications. From there, if you are using REXX, I think it is possible
to even get back error codes from all this, but I really never have
thought much about it..

REXX isn't limited to OS/2 IIRC, no?


Thanks ..

------------------
Mike Luther
[email protected]

[Clay Clear]

Mike,

I have successfully run 32-bit console apps in a BAT file and used
their exit codes within the BAT file. This was under Win98SE.


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