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] Message-ID: <Pine.BSF.4.21.0110160826180.16625-100000@xena.gsicomp.on.ca> In-Reply-To: <200110161002.f9GA2CA08544@shalimar.net.au>
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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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