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Date: Wed, 3 Jul 2013 16:31:20 -0400
From: Christopher Faylor <cgf-use-the-mailinglist-please AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: pty issue causes 'screen' to hang when run from mintty as detached
Message-ID: <20130703203120.GA4528@ednor.casa.cgf.cx>
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On Mon, Jun 17, 2013 at 09:58:35AM -0400, Christopher Faylor wrote:
>On Mon, Jun 17, 2013 at 06:08:27AM -0400, Andrew Schulman wrote:
>>> > Do we have any idea whether the problem is with mintty or with screen?
>>> 
>>> I observed the same behaviour as the OP, but also reproduced it in
>>> rxvt and xterm, so not a mintty issue. Since it works in a console,
>>> the Cygwin pty layer has to be the main suspect, unless screen has
>>> specfic code for Cygwin consoles or ptys?
>>
>>I don't think so, but there's one big, crufty old patch that I had to use to get
>>screen to run a few years ago.
>>
>>The version of screen that we're using now in Cygwin, 4.0.3, is about 8 years
>>old.  There haven't been any official new releases since then, but development
>>has continued and there have been a lot of improvements.  I'm in the process of
>>building an updated package from the latest git, and that version appears not to
>>need any of the patches I used to have to use to get screen to compile and run
>>in Cygwin.
>>
>>So, I suggest that we wait until the new screen test release comes out, within a
>>few days, and see if that fixes the problem.
>
>I looked at this briefly over the weekend and saw a problem in Cygwin's
>pty handling code.  I don't know exactly what the problem is yet but there
>is something not quite right there.  Something is closing a windows handle
>and that's causing a SIGHUP to be sent to the pty owner.  That's not right.
>
>I'll fix this problem eventually but it will be interesting to see if a
>newer screen behaves any better.

This problem should be fixed in the upcoming snapshot.

It was a longstanding bug in the pty code.

Thanks for providing the succinct steps required to duplicate the
problem.

cgf

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