From owner-freebsd-questions@FreeBSD.ORG  Tue Oct 20 15:07:21 2009
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: FreeBSD-Questions@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id BA03B10656A4
	for <FreeBSD-Questions@FreeBSD.org>;
	Tue, 20 Oct 2009 15:07:21 +0000 (UTC)
	(envelope-from dkelly@Grumpy.DynDNS.org)
Received: from smtp.knology.net (smtp.knology.net [24.214.63.101])
	by mx1.freebsd.org (Postfix) with ESMTP id 44D368FC1C
	for <FreeBSD-Questions@FreeBSD.org>;
	Tue, 20 Oct 2009 15:07:20 +0000 (UTC)
Received: (qmail 32528 invoked by uid 0); 20 Oct 2009 15:07:19 -0000
Received: from unknown (HELO Grumpy.DynDNS.org) (24.42.224.110)
	by smtp7.knology.net with SMTP; 20 Oct 2009 15:07:19 -0000
Received: by Grumpy.DynDNS.org (Postfix, from userid 928)
	id D31D128435; Tue, 20 Oct 2009 10:07:18 -0500 (CDT)
Date: Tue, 20 Oct 2009 10:07:18 -0500
From: David Kelly <dkelly@hiwaay.net>
To: FreeBSD-Questions@FreeBSD.org
Message-ID: <20091020150718.GA42322@Grumpy.DynDNS.org>
References: <20091019013337.GA9522@thought.org>
	<72213BBF-5E05-430D-BF9A-FCD2666951C6@hiwaay.net>
	<20091019054344.bb4822ca.freebsd@edvax.de>
	<20091019135805.GA35875@Grumpy.DynDNS.org>
	<20091020050840.e452d7c1.freebsd@edvax.de>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20091020050840.e452d7c1.freebsd@edvax.de>
User-Agent: Mutt/1.4.2.3i
Cc: 
Subject: Re: need C help, passing char buffer[] by-value....
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: FreeBSD-Questions@FreeBSD.org
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 20 Oct 2009 15:07:21 -0000

On Tue, Oct 20, 2009 at 05:08:40AM +0200, Polytropon wrote:
> On Mon, 19 Oct 2009 08:58:05 -0500, David Kelly <dkelly@hiwaay.net> wrote:
> > On Mon, Oct 19, 2009 at 05:43:44AM +0200, Polytropon wrote:
> > > to make sure s is not NULL, or testing for it explicitely like
> > > 
> > > 	if(!s)
> > > 		... error handling here ...
> > 
> > You are missing my point that *s == 0 is not a good out of bounds
> > range check.
> 
> That's correct. Test != NULL just ensures that it is not a NULL
> pointer. Range checking should always be applied additionally.

Polytropon's "if(!s)" is testing for null pointer and thats a useful
test, but I'm testing for a pointer to a null which is something else.

Access through a null pointer should result in a memory violation core
dump.

-- 
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.