Date: Tue, 16 Oct 2001 22:49:42 +1000 From: Greg Black <gjb@gbch.net> 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: <nospam-1003236582.62800@mx1.gbch.net> In-Reply-To: <200110161002.f9GA2CA08544@shalimar.net.au> of Tue, 16 Oct 2001 20:02:11 %2B1000 References: <200110160353.f9G3rO728525@harmony.village.org> <Pine.LNX.4.33.0110152249220.8479-100000@organ.cs.byu.edu> <20011016013834.E293@blossom.cjclark.org> <200110161002.f9GA2CA08544@shalimar.net.au>
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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.
|
| Has this changed without me noticing?
This is an absurd claim -- under K&R C and ISO C there is no
equivalence between these two things.
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