Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!cornell!uw-beaver!teknowledge-vaxc!sri-unix!quintus!ok
From: ok@quintus.UUCP (Richard A. O'Keefe)
Newsgroups: comp.lang.c
Subject: Re: How big is the argv[] array?
Message-ID: <507@quintus.UUCP>
Date: 6 Oct 88 00:00:40 GMT
References: <1239500004@osiris.cso.uiuc.edu> <8631@smoke.ARPA> <4206@bsu-cs.UUCP>
Reply-To: ok@quintus.UUCP (Richard A. O'Keefe)
Organization: Quintus Computer Systems, Inc.
Lines: 31

In article <4206@bsu-cs.UUCP> dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
>In article <8631@smoke.ARPA> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
>>argv[argc] is supposed to be a null pointer...
>Since this is comp.lang.c and not a UNIX newsgroup, the following
>footnote from "Advanced UNIX Programming" by Marc J. Rochkind (p 105)
>is relevant:
>
>     "The C Programming Language" does not state anywhere that argv[argc]
>     is NULL.  Neither do most UNIX manuals.

The System V Interface Definition says (Vol 1, Page 71, 1st paragraph)
	"argv is terminated by a null pointer", and
	"envp is terminated by a null-pointer".
The 4.2BSD manual page says
	"the array of pointers is terminated by a null pointer".
The VAX-11 C manual (for VMS) says on page 24-5
	"The last element of [argv] is always the null pointer (0).", and
	"The last element in envp must be the null pointer (0)."
On IBM mainframes, SAS Lattice C (C-101, p 4.6) says that
	"argv[argc] is 0"
and the IBM C Compiler reference manual says on page 8.3 that
there is a null pointer after the arguments in argv[].  (It should be
noted that the SAS manual gives an example of calling C from Fortran
which violates this convention, but that example also violates the convention
that the elements of argv[] are pointers to strings.)

So, assuming that !argv[argc] is portable between System V, 4.2,
VMS, and IBM mainframes.

Which are the implementations of C where argv[] is present but argv[argc]
is not defined?