X-Recipient:	archive-cygwin AT delorie DOT com
X-SWARE-Spam-Status:	No, hits=-0.5 required=5.0 tests=AWL,BAYES_50,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE
X-Spam-Check-By:	sourceware.org
MIME-Version:	1.0
In-Reply-To:	<416096c61003091250p186ac05bj8b0b4f7c2b224c85@mail.gmail.com>
References:	<20100309180647 DOT GB3442 AT sunray DOT mv DOT cariden DOT com> <416096c61003091250p186ac05bj8b0b4f7c2b224c85 AT mail DOT gmail DOT com>
Date:	Mon, 31 May 2010 12:39:30 +0100
Message-ID:	<AANLkTimJ0Ytcq-GP7LxIxT2uUpbsPi8B9rk-bGKcMJEF@mail.gmail.com>
Subject:	Re: "can't create master tty" errors
From:	Andy Koppe <andy DOT koppe AT gmail DOT com>
To:	Cesar Crusius <cesar AT cariden DOT com>, cygwin AT cygwin DOT com
X-IsSubscribed:	yes
Mailing-List:	contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id:	<cygwin.cygwin.com>
List-Unsubscribe:	<mailto:cygwin-unsubscribe-archive-cygwin=delorie DOT com AT cygwin DOT com>
List-Subscribe:	<mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive:	<http://sourceware.org/ml/cygwin/>
List-Post:	<mailto:cygwin AT cygwin DOT com>
List-Help:	<mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/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

On 9 March 2010 21:50, Andy Koppe wrote:
> Cesar Crusius:
>> I am using Cygwin and SSH to do automated remote builds using Visual
>> C++. It works for a few days, but invariably things start failing with
>> messages like these (this one from a build log):
>>
>> Makefile:9: MakePID: 5964
>> =C2=A0 =C2=A0 =C2=A01 [main] env 2748 C:\cygwin\bin\env.exe: *** fatal e=
rror - can't create master tty
>
> The number of tty devices is limited, so the first thing to check is
> whether your build system simply leaves too many sessions open, by
> checking the output of 'ps'.
>
> If not, it might be to do with the following. If you open a couple of
> terminals, they're assigned =C2=A0tty0 and tty1. If you then close tty1 a=
nd
> open another terminal, that again becomes tty1. But if you close tty0,
> and open yet another one, that becomes tty2 rather than tty0.
>
> That appears to be the general rule: a new terminal gets the next ID
> above the current highest one. This means, however, that if opening
> and closing of terminal sessions is interleaved in certain ways,
> Cygwin might eventually run out of terminal IDs, even if only few of
> them are actually used. High numbers in the TTY column of the 'ps'
> output would point to that.
>
> Cgf, am I talking rubbish here?

For the record: I was. What I observed there was due to a bug in
mintty: a new mintty session spawned using Alt+F2 inherited the pty
file descriptor from its parent, and by extension, also the
descriptors from its previous ancestors. Due to that, a pty device
wasn't released until the session that actually used it and all the
sessions spawned from that were closed. Fixed for mintty-0.7.

So pty numbers are reused just fine, and I can't help with the OP's issue.

Andy

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

- Raw text -