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From: jvc@mirror.UUCP
Newsgroups: comp.lang.c
Subject: Re: 1 Turbo C question (used to be 2)
Message-ID: <236100002@mirror>
Date: Tue, 1-Sep-87 08:36:00 EDT
Article-I.D.: mirror.236100002
Posted: Tue Sep  1 08:36:00 1987
Date-Received: Sat, 5-Sep-87 03:32:59 EDT
References: <9061@brl-adm.ARPA>
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Nf-ID: #R:brl-adm.ARPA:-906100:mirror:236100002:000:2106
Nf-From: mirror.UUCP!jvc    Sep  1 08:36:00 1987


/* Written  7:35 pm  Aug 30, 1987 by toma@killer.UUCP in comp.lang.c */
>You have something in dos called errorlevel that will give you the value
>you exit()ed with. This could be used in a batch file like this...
>
>.	REM RUN MAIN PROGRAM
>.	MAINPGM
>.	IF ERRORLEVEL 0 GOTO GOOD
>.	IF ERRORLEVEL 1 GOTO BAD
>.	IF ERRORLEVEL 2 GOTO HAWAII
>.	:GOOD
>.	ECHO WE GOT A GOOD RETURN
>.	GOTO END
>.	:BAD
>.	ECHO WE GOT A BAD RETURN
>.	GOTO END
>.	:HAWAII
>.	ECHO WE ARE GOING TO HAWII
>.	:END
>.	EXIT
>
>the number following 'ERRORLEVEL' will be the number you exited with.

He's got the right idea but it won't work as coded.  Refer to page
7-34 of DOS 3.2 Reference, paragraph 2 (approx.):
	"ERRORLEVEL number is true if the previous program
         had an exit code of number or higher.  The number 
	 is specified as a decimal value."

In order for the above code segment to work you must reverse the 
order of the IF statements.  It would also be wise to cover the 
case in which the program might return a 3 or greater since in this
example you only want to GOTO HAWAII if you get a return of 2.
 
Also note that EXIT won't terminate a batch file and therefore
should not be in this code segment. (DOS 3.1, 3.2)

Corrected code segment:

	REM RUN MAIN PROGRAM
	MAINPGM
	REM Look at return codes
	REM A return of 3 or greater is unexpected
	IF ERRORLEVEL 3 GOTO UNEXPECTED
	REM Now we can test for 2 (or greater but we've already 
	REM  handled values greater than 2)
	IF ERRORLEVEL 2 GOTO HAWAII
	REM Test for return of 1
	IF ERRORLEVEL 1 GOTO BAD
	REM Test for return of 0
	IF ERRORLEVEL 0 GOTO GOOD
	:GOOD
	ECHO WE GOT A GOOD RETURN
	GOTO END
	:BAD
	ECHO WE GOT A BAD RETURN
	GOTO END
	:HAWAII
	ECHO WE ARE GOING TO HAWII
	GOTO END
	:UNEXPECTED
	ECHO Unexpected return value ( >=3 )
	:END
	REM No more commands after this so execution terminates

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Jim Champeaux	jvc@mirror.TMC.COM
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