From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1M6VzE-0007N6-Pj
	for qemu-devel@nongnu.org; Tue, 19 May 2009 16:32:32 -0400
Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43)
	id 1M6Vz9-0007DF-K2
	for qemu-devel@nongnu.org; Tue, 19 May 2009 16:32:31 -0400
Received: from [199.232.76.173] (port=34611 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1M6Vz9-0007Cw-AH
	for qemu-devel@nongnu.org; Tue, 19 May 2009 16:32:27 -0400
Received: from mail2.shareable.org ([80.68.89.115]:33905)
	by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32)
	(Exim 4.60) (envelope-from <jamie@shareable.org>) id 1M6Vz8-00052U-Rc
	for qemu-devel@nongnu.org; Tue, 19 May 2009 16:32:27 -0400
Date: Tue, 19 May 2009 21:32:23 +0100
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [Qemu-devel] [PATCH] fix qemu_malloc() error check for size==0
Message-ID: <20090519203223.GC3986@shareable.org>
References: <Pine.LNX.4.64.0905190410290.3632@linmac.oyster.ru>
	<8763fxvbfk.fsf@pike.pond.sub.org>
	<Pine.LNX.4.64.0905191635360.2165@linmac.oyster.ru>
	<87octpnrhr.fsf@pike.pond.sub.org>
	<Pine.LNX.4.64.0905191748270.3797@linmac.oyster.ru>
	<20090519142847.GC4254@blackpad>
	<Pine.LNX.4.64.0905191840240.4038@linmac.oyster.ru>
	<20090519145653.GE4254@blackpad>
	<Pine.LNX.4.64.0905191922110.4116@linmac.oyster.ru>
	<20090519154317.GF4254@blackpad>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20090519154317.GF4254@blackpad>
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: malc <av1474@comtv.ru>, Markus Armbruster <armbru@redhat.com>, qemu-devel@nongnu.org

Eduardo Habkost wrote:
> Now, _that_ sounds like a really bad idea. realloc(NULL, n) is specified
> to be equivalent to malloc(n).

No it isn't.  You can't make that substitution.

In the case where n == 0, realloc(NULL, n) is guaranteed to not
allocate anything and return NULL, whereas malloc(n) does not
guarantee that and in fact doesn't do that on a lot of implementations.

-- Jamie