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To:	Ken Brown <kbrown AT cornell DOT edu>
Subject:	Re: Another pipe-related problem?
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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")
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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>
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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.


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