From owner-freebsd-stable  Tue Oct 16  5:35:25 2001
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Date: Tue, 16 Oct 2001 08:27:06 -0400 (EDT)
From: Matthew Emmerton <matt@gsicomp.on.ca>
To: Zero Sum <count@shalimar.net.au>
Cc: cjclark@alum.mit.edu, "Crist J. Clark" <cristjc@earthlink.net>,
	Heath Nielson <heath@cs.byu.edu>,
	Warner Losh <imp@harmony.village.org>,
	David Marker <marker_d@yahoo.com>, freebsd-stable@FreeBSD.ORG
Subject: Re: setenv() cores with NULL value [was Re: Gdm proplem on 4.4]
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On Tue, 16 Oct 2001, Zero Sum wrote:

> On Tuesday 16 October 2001 18:38, Crist J. Clark wrote:
> 
> > > 
> > > setenv("TEST1", "", 1);
> > > setenv("TEST2", NULL, 1);
> > 
> > A huge difference. In the first case, the second argument is a
> > pointer aimed at a string which contains the bytes, '\0'. In the
> > second case, we have a null pointer. Null pointers point at nothing.
> 
> I had that out with a compiler manufacturer long, long ago.  At that 
> time it was a requirement for a 'correct' C compiler to regard a null 
> pointer and a pointer to a null string as sematically equivalent.

I doubt that this was ever the case.  A null string and a null pointer are
two different things entirely.  Treating them as equal would be wrong.

--
Matt Emmerton


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