Mailing-List: contact cygwin-developers-help AT sourceware DOT cygnus DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-developers-subscribe AT sourceware DOT cygnus DOT com>
List-Archive: <http://sourceware.cygnus.com/ml/cygwin-developers/>
List-Post: <mailto:cygwin-developers AT sourceware DOT cygnus DOT com>
List-Help: <mailto:cygwin-developers-help AT sourceware DOT cygnus DOT com>, <http://sourceware.cygnus.com/ml/#faqs>
Sender: cygwin-developers-owner AT sourceware DOT cygnus DOT com
Delivered-To: mailing list cygwin-developers AT sourceware DOT cygnus DOT com
From: Chris Faylor <cgf AT cygnus DOT com>
Date: Sat, 20 May 2000 02:28:40 -0400
To: cygwin-developers AT sourceware DOT cygnus DOT com
Subject: Win95 problems revealed?
Message-ID: <20000520022840.A10995@cygnus.com>
Mail-Followup-To: cgf AT cygnus DOT com, cygwin-developers AT sourceware DOT cygnus DOT com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.1.12i

I may have figured out at least one of the long long long standing
problems with Windows 95.  The function GetThreadContext seems to
sometimes return bogus information.

This function is used by the signal handler code to figure out things
about the thread which is supposed to receive a signal.  In particular,
cygwin gets information concerning the stack pointer and current PC from
this function.  So, if the information is wrong, the results are
catastrophic.

I've really ripped the signal handler apart in the last few months and
this has been partly responsible for revealing the Windows 95 bug.  I
noticed the problem by running rxvt continuously on my Windows 95
system.  It would randomly cause a blue screen.

Liberal use of printfs pinpointed the problem.

I've worked around the problem in the current snapshot so I would be
interested in hearing if I have broken anything before I unleash this
on the world.

So, if you have negative experiences with the latest code on Windows 95
or NT, I'd like to hear about it.

Please send email to cygwin-developers with your experiences.

Thanks,
cgf