From owner-freebsd-hackers@FreeBSD.ORG  Fri Jun 30 04:58:40 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 63A9216A407
	for <freebsd-hackers@freebsd.org>; Fri, 30 Jun 2006 04:58:40 +0000 (UTC)
	(envelope-from hnazfoo@googlemail.com)
Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.186])
	by mx1.FreeBSD.org (Postfix) with ESMTP id AC76B446EB
	for <freebsd-hackers@freebsd.org>; Fri, 30 Jun 2006 04:58:39 +0000 (GMT)
	(envelope-from hnazfoo@googlemail.com)
Received: by nf-out-0910.google.com with SMTP id c29so199267nfb
	for <freebsd-hackers@freebsd.org>; Thu, 29 Jun 2006 21:58:38 -0700 (PDT)
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=googlemail.com;
	h=received:date:from:to:subject:message-id:mail-followup-to:references:mime-version:content-type:content-disposition:in-reply-to:user-agent;
	b=BrX9KAmTFUDalSAZubOQR9iFS9acksNN9oNiGZa7wMINjivVr8uoOvjGRYjO+dElYQHYlpwsbHFmr8dHxrDpgwH/keuFa3vHYndrHUZ9Z9jhu9ssdrqJM/KiSSniK6k8OUkUpP/0h4fUpE8kuyybyGX4LyZIq6STGXwXBaCpMhM=
Received: by 10.48.223.17 with SMTP id v17mr257518nfg;
	Thu, 29 Jun 2006 21:58:38 -0700 (PDT)
Received: from localhost ( [217.65.22.47])
	by mx.gmail.com with ESMTP id p72sm1115736nfc.2006.06.29.21.58.36;
	Thu, 29 Jun 2006 21:58:37 -0700 (PDT)
Date: Fri, 30 Jun 2006 06:59:37 +0200
From: Johannes Weiner <hnazfoo@googlemail.com>
To: freebsd-hackers@freebsd.org
Message-ID: <20060630045937.GB97868@leiferikson.flosken.lan>
Mail-Followup-To: freebsd-hackers@freebsd.org
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>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <m33bdnhnv7.fsf@merlin.emma.line.org>
User-Agent: mutt-ng/devel-r804 (FreeBSD)
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: Fri, 30 Jun 2006 04:58:40 -0000

Hi,

On Thu, Jun 29, 2006 at 07:29:16PM +0200, Matthias Andree wrote:
> No, sir. Operator precedence: assign first, and then compare, thus the
> comparison will always be true (else you'd be comparing to undefined
> values, which isn't any better).  You might as well write:
> 
>  foo = malloc(0);
>  /* make noise */

Ok, just for having it done:

	if (foo == (foo = some_val))

.. would be right to check if foo stayed the same. No?

> There is no way to see a 0x800 return from malloc(0) as "error".

So noone should actually use malloc(0) and check the size_t argument before
passing it, I guess.

Hannes
-- 
One must still have chaos in oneself to be able to give
a birth to a dancing star.