From owner-freebsd-hackers@FreeBSD.ORG  Sat Jul  1 09:07:10 2006
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
X-Original-To: freebsd-hackers@freebsd.org
Delivered-To: freebsd-hackers@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id CABF916A557
	for <freebsd-hackers@freebsd.org>; Sat,  1 Jul 2006 09:07:10 +0000 (UTC)
	(envelope-from matthias.andree@gmx.de)
Received: from mail.gmx.net (mail.gmx.de [213.165.64.21])
	by mx1.FreeBSD.org (Postfix) with SMTP id F251A43E85
	for <freebsd-hackers@freebsd.org>; Sat,  1 Jul 2006 08:35:51 +0000 (GMT)
	(envelope-from matthias.andree@gmx.de)
Received: (qmail invoked by alias); 01 Jul 2006 08:35:50 -0000
Received: from p509146DC.dip0.t-ipconnect.de (EHLO m2a2.dyndns.org)
	[80.145.70.220]
	by mail.gmx.net (mp030) with SMTP; 01 Jul 2006 10:35:50 +0200
X-Authenticated: #428038
Received: from localhost (localhost [127.0.0.1])
	by merlin.emma.line.org (Postfix) with ESMTP id C2ACD2006C2;
	Sat,  1 Jul 2006 10:35:48 +0200 (CEST)
Received: from m2a2.dyndns.org ([127.0.0.1])
	by localhost (m2a2.dyndns.org [127.0.0.1]) (amavisd-new, port 10024)
	with ESMTP id 12406-09; Sat,  1 Jul 2006 10:35:47 +0200 (CEST)
Received: by merlin.emma.line.org (Postfix, from userid 500)
	id 0EA46200719; Sat,  1 Jul 2006 10:35:47 +0200 (CEST)
From: Matthias Andree <matthias.andree@gmx.de>
To: Pat Lashley <patl+freebsd@volant.org>
In-Reply-To: <417C9B11412FF8C17A1AD483@Zelazny> (Pat Lashley's message of
	"Fri, 30 Jun 2006 12:30:13 -0400")
References: <20060628181045.GA54915@curry.mchp.siemens.de>
	<20060629054222.GA92895@leiferikson.flosken.lan>
	<m3bqsceyf2.fsf@merlin.emma.line.org>
	<20060629162319.GA94921@leiferikson.flosken.lan>
	<m33bdnhnv7.fsf@merlin.emma.line.org>
	<20060630045937.GB97868@leiferikson.flosken.lan>
	<417C9B11412FF8C17A1AD483@Zelazny>
X-PGP-Key: http://home.pages.de/~mandree/keys/GPGKEY.asc
Date: Sat, 01 Jul 2006 10:35:47 +0200
Message-ID: <m3hd21g1ss.fsf@merlin.emma.line.org>
User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.3 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Virus-Scanned: amavisd-new at emma.line.org
X-Y-GMX-Trusted: 0
Cc: freebsd-hackers@freebsd.org, Johannes Weiner <hnazfoo@googlemail.com>
Subject: Re: Return value of malloc(0)
X-BeenThere: freebsd-hackers@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Technical Discussions relating to FreeBSD
	<freebsd-hackers.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>, 
	<mailto:freebsd-hackers-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-hackers>
List-Post: <mailto:freebsd-hackers@freebsd.org>
List-Help: <mailto:freebsd-hackers-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-hackers>,
	<mailto:freebsd-hackers-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 01 Jul 2006 09:07:11 -0000

Pat Lashley <patl+freebsd@volant.org> writes:

> BUT, that said, the safest and most portable coding practice would be:
>
>        // The C standard does not require malloc(0) to return NULL;
>        // but whatever it returns MUST NOT be dereferenced.
>        ptr = ( size == 0 ) ? NULL : malloc( size ) ;

Safest (avoiding null derefence) would instead be:

       ptr = malloc(size ? size : 1);

BTW: // is not a valid C89 comment, but a GCC-ism.

-- 
Matthias Andree