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Date: Mon, 27 Oct 2003 14:11:23 +0000
From: Tony Finch <dot@dotat.at>
To: Harti Brandt <brandt@fokus.fraunhofer.de>
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References: <20031027144140.V63585@beagle.fokus.fraunhofer.de>
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cc: standards@freebsd.org
cc: sparc64@freebsd.org
Subject: Re: 64bit NULL?
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On Mon, Oct 27, 2003 at 02:49:51PM +0100, Harti Brandt wrote:
> 
> According to ISO-C NULL is a symbol that
> defines a null pointer so that:
> 
> 	execl(..., NULL)
> 
> appears to be legal, yet will probably cause failure on FreeBSD-sparc64.

No, NULL is an implementation-defined null pointer constant, not a null
pointer. The difference is that a null pointer constant is an integer
constant expression that evaluates to zero (optionally cast to void*),
and a null pointer is a null pointer constant converted to a pointer type
(which might involve changes in representation). Therefore using a bare
NULL to terminate the execl argument list is not in general legal.

Tony.
-- 
f.a.n.finch  <dot@dotat.at>  http://dotat.at/
GERMAN BIGHT: SOUTHWEST 5 OR 6. OCCASIONAL RAIN. MODERATE OR GOOD.