X-Recipient: archive-cygwin AT delorie DOT com
DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 34C503857818
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cygwin.com;
	s=default; t=1636569982;
	bh=hSk9GooMs33tCupuGRbzvfcOm9AlaM8DRKoVY2l1tOw=;
	h=To:Subject:References:Date:In-Reply-To:List-Id:List-Unsubscribe:
	 List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc:
	 From;
	b=xYReafPS7HeVNfD4+sNiDSPM89e/Dd4qUb6tFTIHb5gDfdFuhTfydYw4jglJ9+yFj
	 +RdQwuM2o9L8hjzD/TWB0dYbhOGWH5ZfKI9l779OYLiuANn6JHE1AF1KFUTB8aYnd3
	 ujuFpxeCMrJiwVprBDlXSEpvw/zDbBiUbqagaVtQ=
X-Original-To: cygwin AT cygwin DOT com
Delivered-To: cygwin AT cygwin DOT com
DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 51DC3385803B
To: Ken Brown <kbrown AT cornell DOT edu>
Subject: Re: Another pipe-related problem?
References: <f5br1bqaj11 DOT fsf AT ecclerig DOT inf DOT ed DOT ac DOT uk>
 <05c4180e-396b-4af3-ac0c-2ab8125df17e AT cornell DOT edu>
 <f5bk0hh8uox DOT fsf AT ecclerig DOT inf DOT ed DOT ac DOT uk>
 <eb8d7d4f-d1ed-6f30-2ac3-1b24166243d9 AT cornell DOT edu>
 <0971ace1-5ee8-bdcc-5fd9-4551b294ebf8 AT cornell DOT edu>
 <75197fd0-d5da-3236-a7df-b8ffc3f67da7 AT cornell DOT edu>
 <bb6c5229-ce46-5fb3-c8c3-a19c0826d8d5 AT cornell DOT edu>
 <4b937b32-e348-19d2-2406-c55fa12e20a3 AT cornell DOT edu>
 <f5bfss33oxi DOT fsf AT ecclerig DOT inf DOT ed DOT ac DOT uk>
 <83df50b8-5c0c-41b9-1e9e-4ea6bfa3d69f AT cornell DOT edu>
Date: Wed, 10 Nov 2021 18:42:31 +0000
In-Reply-To: <83df50b8-5c0c-41b9-1e9e-4ea6bfa3d69f@cornell.edu> (Ken Brown's
 message of "Wed\, 10 Nov 2021 13\:03\:09 -0500")
Message-ID: <f5bbl2r3l9k.fsf@ecclerig.inf.ed.ac.uk>
User-Agent: Gnus/5.101 (Gnus v5.10.10) XEmacs/21.5-b34 (linux)
MIME-Version: 1.0
X-Edinburgh-Scanned: at seine.is.ed.ac.uk
X-Spam-Status: No, score=-2.2 required=5.0 tests=BAYES_00, KAM_DMARC_STATUS,
 RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, SPF_HELO_PASS, SPF_PASS,
 TXREP autolearn=ham autolearn_force=no version=3.4.4
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on
 server2.sourceware.org
X-BeenThere: cygwin AT cygwin DOT com
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: General Cygwin discussions and problem reports <cygwin.cygwin.com>
List-Unsubscribe: <https://cygwin.com/mailman/options/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=unsubscribe>
List-Archive: <https://cygwin.com/pipermail/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-request AT cygwin DOT com?subject=help>
List-Subscribe: <https://cygwin.com/mailman/listinfo/cygwin>,
 <mailto:cygwin-request AT cygwin DOT com?subject=subscribe>
From: "Henry S. Thompson via Cygwin" <cygwin AT cygwin DOT com>
Reply-To: "Henry S. Thompson" <ht AT inf DOT ed DOT ac DOT uk>
Cc: cygwin AT cygwin DOT com
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie DOT com AT cygwin DOT com>

Ken Brown writes:

> ...

> The main change was that we stopped using Win32 Overlapped I/O
> (https://docs.microsoft.com/en-us/windows/win32/sync/synchronization-and-overlapped-input-and-output)
> and switched to using the NT API.  As a result, pipe I/O became much
> more efficient.  It wouldn't surprise me if the efficiency alone is
> what exposed the bug.
>
> The good news is that the bug doesn't seem to occur in XEmacs 21.4
> (on 32-bit Cygwin).  So one way to approach this would be to bisect
> the XEmacs git repo to find the commit that introduced the bug.
> You'd probably have to do the work on 32-bit Cygwin since, if I
> remember correctly, XEmacs 21.4 didn't build on 64-bit Cygwin.

Right, although I _suspect_ it will be in 64-bit-only code.  Easy
enough to find out, once I resurrect a 32-bit install on a spare
machine that I can run 3.3 on (I use XEmacs all day every day from my
day job, so I need to stay with 3.2 until we fix this).

So, this may take a while, unless someone else hits the problem and
finds a simpler test case.

Thanks again,

ht
-- 
       Henry S. Thompson, School of Informatics, University of Edinburgh
      10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440
                Fax: (44) 131 650-4587, e-mail: ht AT inf DOT ed DOT ac DOT uk
                       URL: http://www.ltg.ed.ac.uk/~ht/
 [mail from me _always_ has a .sig like this -- mail without it is forged spam]

The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.


-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple