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From: klee@chico.pa.dec.com (Ken Lee)
Newsgroups: comp.unix.wizards
Subject: Re: Why isn't argv[argc]==(char *)0 ?
Message-ID: <2108@bacchus.dec.com>
Date: 15 Nov 89 23:00:22 GMT
References: <547.nlhp3@oracle.nl>
Sender: news@decwrl.dec.com
Reply-To: klee@decwrl.dec.com
Organization: DEC Western Software Laboratory
Lines: 14

In article <547.nlhp3@oracle.nl>, bengsig@oracle.nl (Bjorn Engsig) writes:
=> The execv family of system calls all have  char *argv[]  as their second
=> parameter, and you are required to put an endmarker as  (char *)0  in it.
=> On the other hand, main has  int argc  and  char *argv[]  but here, the
=> endmarker has disappeared. 

Most (all?) UNIXes have argv[argc]==0, though many, especially System V
based ones, don't document it.  Note that p.115 of the new K&R says
"the [ANSI C] standard requires that argv[argc] be a null pointer".

Ken Lee
DEC Western Software Laboratory, Palo Alto, Calif.
Internet: klee@decwrl.dec.com
uucp: uunet!decwrl!klee