Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sources.redhat.com/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Date: Mon, 24 Feb 2003 21:28:07 -0500
From: Christopher Faylor <cgf-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: 1.3.20: mmap with nonzero file offset results in seg fault (Win2k )"
Message-ID: <20030225022807.GD24688@redhat.com>
Reply-To: cygwin AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
References: <754324CDE8E4EE4498D8E0357D913685D4D16A AT saab-bt DOT act DOT cmis DOT CSIRO DOT AU>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <754324CDE8E4EE4498D8E0357D913685D4D16A@saab-bt.act.cmis.CSIRO.AU>
User-Agent: Mutt/1.5.1i

On Tue, Feb 25, 2003 at 12:49:45PM +1100, brett DOT matson AT csiro DOT au wrote:
>
>Accessing the mapped region of memory after an mmap call 
>with a non-zero offset results in a seg fault. A zero 
>offset will not result in a seg fault.
>
>Cygwin1.dll version 1.3.19 doesn't experience this problem.  
>Cygcheck output is attached.
>
>Example:
>
>if (rslt = mmap(0, size, prot, MAP_SHARED,  fd, offset)) 
>    == MAP_FAILED) {
>} else {
>    printf("%d", rslt[0]); // seg fault
>}
>AND
>if (rslt = mmap(0, size, prot, MAP_SHARED,  fd, 0)) 
>    == MAP_FAILED) {
>} else {
>    printf("%d", rslt[0]); // no seg fault (zero offset)
>}

The above is bogus code since rslt will be equal to either 1 or 0
depending on whether mmap failed or not.

Please provide a real working test case which can be cut, pasted,
compiled, linked, and run, if you want help.  The theory is that,
if you want help, you reduce the barrier of providing the help as
much as possible.  Providing buggy examples isn't going to do that.

cgf
--
Please use the resources at cygwin.com rather than sending personal email.
Special for spam email harvesters: send email to aaaspam AT sourceware DOT org
and be permanently blocked from mailing lists at sources.redhat.com

--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Bug reporting:         http://cygwin.com/bugs.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/