X-Recipient: archive-cygwin AT delorie DOT com
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:in-reply-to
	:references:mime-version:content-type:content-transfer-encoding;
	 q=dns; s=default; b=CziDatTAKOvto/yfLfah06o7ZbnmMfZAup+6pLYUEbr
	3RRgKc0yPUmeAnQ2ntXhuejv4dyIEwKYp0VjBMnMpF5fd0/hE7lP54RzC9D7PEbh
	RdFw5WBAigboIHhY8etA5ywX3X6YhyQq+/hWtUfsb4xiSb+JxT8xNA1bRJmEamsI
	=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:in-reply-to
	:references:mime-version:content-type:content-transfer-encoding;
	 s=default; bh=YCcPHntjsDpVid3Y3uKI+Rmauac=; b=duwDx59Ow04lpz/oZ
	6x7UmxKw3sku1+FO4qZNQNVm2U81jhbQNB2iUhwG3vofwz/lrK/8Xwqb9tRFCUoY
	zbbO8DdWAaW8QPKaGbs5Fkfh9hmgFpFEXrMugSYZJjupKyyCdkRhh+5C2pO6GjIC
	j/z3jJAlvTZs211xlLK0SQlwW8=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.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
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2
X-HELO: mailscanner02.zoner.fi
Date: Tue, 24 Feb 2015 16:16:01 +0200
From: Lasse Collin <lasse DOT collin AT tukaani DOT org>
To: cygwin AT cygwin DOT com
Subject: Re: Clearing O_NONBLOCK from a pipe may lose data
Message-ID: <20150224161601.68f0a08c@tukaani.org>
In-Reply-To: <20150224110953.GF437@calimero.vinschen.de>
References: <20150222220747 DOT 789401d2 AT tukaani DOT org>	<20150223105653 DOT GG437 AT calimero DOT vinschen DOT de>	<20150223122345 DOT GM437 AT calimero DOT vinschen DOT de>	<54EC2566 DOT 4030703 AT towo DOT net>	<20150224110953 DOT GF437 AT calimero DOT vinschen DOT de>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
X-Antivirus-Scanner: Clean mail though you should still use an Antivirus
Received-SPF: none
X-IsSubscribed: yes

On 2015-02-24 Corinna Vinschen wrote:
> On Feb 24 08:16, Thomas Wolff wrote:
> > Am 23.02.2015 um 13:23 schrieb Corinna Vinschen:
> > >On Feb 23 11:56, Corinna Vinschen wrote:
> > >>On Feb 22 22:07, Lasse Collin wrote:
> > >>>Alternative idea: Would there be a significant downside if Cygwin
> > >>>remembered if non-blocking mode was enabled at some point and
> > >>>close() would use that flag instead of the current (non)blocking
> > >>>status to determine if the background thread hack should be used?
> > >>No, that should be doable with very minor effort.
> > >That's still an option, of course.
> > I think that sounds like a solution.
> 
> I applied a matching patch for this:
> 
> https://cygwin.com/ml/cygwin-cvs/2015-q1/msg00079.html
> 
> Please give it a try.

I applied the patches to the snapshot 20150223 and it works now. Thank
you.

I'm going to release xz 5.2.1 in a day or two. Should that release have
a workaround for this Cygwin bug? The workaround would avoid using
O_NONBLOCK on stdout. It adds a race condition to signal handling in xz
but it's usually a very minor issue (xz 5.0.x has the race and no one
has complained). On the other hand, the fixes to the threading bugs are
somewhat important for xz too, so maybe I should just add a note that
xz 5.2.x isn't safe on Cygwin yet but will be in the (somewhat) near
future?

On 2015-02-23 Corinna Vinschen wrote:
> The idea was always that you can run Cygwin processes without having
> to install services, That's why we were always trying to implement as
> much inside the restrictions of the DLL and not rely on an external
> service like cygserver.  The only notable exception from this rule so
> far is XSI IPC, which requires cygserver to run.  SOmehow it would be
> nice if we could keep it that way and not go full "Windows subsytem
> mode"...

I agree, keeping it that way would be nice.

-- 
Lasse Collin  |  IRC: Larhzu @ IRCnet & Freenode

--
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