Xref: utzoo comp.sys.ibm.pc:24199 comp.lang.c:16014
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From: sme@computing-maths.cardiff.ac.uk (Simon Elliott)
Newsgroups: comp.sys.ibm.pc,comp.lang.c
Subject: Re: system() always returns 0?
Summary: system starts up command.com, which always succeeds
Keywords: MSC5.0
Message-ID: <611@cf-cm.UUCP>
Date: 1 Feb 89 09:58:59 GMT
References: <782@hawkmoon.MN.ORG>
Organization: University of Wales College of Cardiff, Cardiff, WALES, UK.
Lines: 28

In article <782@hawkmoon.MN.ORG>, det@hawkmoon.MN.ORG (Derek E. Terveer) writes:
> Has anyone encountered a problem with the Microsoft C 5.0 compiler always
> returning a 0 from the system() call, no matter what the actual command
> executed by system() returns?
  
> -- 
> Derek Terveer  det@hawkmoon.MN.ORG || ..!uunet!rosevax!elric!hawkmoon!det

The problem is that system works by constructing a "command /c yourcommand",
thus letting commnad.com do the work of looking down the path, etc.
command.com _always_ succeeds, so system returns 0, always.  You have to do
the work yourself, and use one of the spawn/exec functions if you want
meaningful status information.

I have used this behaviour of command.com in makefiles when i want to
clean up files which may not be there.  Some versions of make will croak
if the file is not there, since the 'del' is a builtin, but command /c del
will always succeed, and the make continues.




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