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Date: Fri, 15 Mar 2002 23:28:03 +0100
From: Corinna Vinschen <cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Latest poll() hangs again (was Re: poll() bugs and patch)
Message-ID: <20020315232803.L29574@cygbert.vinschen.de>
Mail-Followup-To: cygwin AT cygwin DOT com
References: <20020313181423 DOT C29574 AT cygbert DOT vinschen DOT de> <LOBBKDBPKEGJJFKNFHKBCEPEGJAA DOT boriss AT web DOT de> <20020314131554 DOT I29574 AT cygbert DOT vinschen DOT de> <20020315200120 DOT GA2484 AT tishler DOT net> <20020315221940 DOT J29574 AT cygbert DOT vinschen DOT de> <20020315213321 DOT GA6540 AT redhat DOT com>
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On Fri, Mar 15, 2002 at 04:33:21PM -0500, Chris Faylor wrote:
> On Fri, Mar 15, 2002 at 10:19:40PM +0100, Corinna Vinschen wrote:
> >On Fri, Mar 15, 2002 at 03:01:21PM -0500, Jason Tishler wrote:
> >> Please revert this patch or modify it so that poll() does not hang.
> >
> >I don't think reverting is the way to go.  One of the problems
> >[...]
> >Unfortunately SUSv2 doesn't handle that special case.  That's
> >a pity.
> >
> >However, we could revert to handle invalid_fds again and then call
> >cygwin_select only if timeout != -1.
> >
> >Comments?  Boris?  Jason?  Anybody else?
> 
> How does linux handle these cases?

Just tested.  It returns immediately if all fd's are invalid,
regardless of the timeout value.  So there's actually no need
to call cygwin_select if all fd's are invalid.  I'm not quite
sure about the other border cases, Boris is talking about though.
This requires further testing.  Sigh, I'd hoped that somebody
else is doing that this time...

I'm inclined to revert the patch and ask Boris to investigate
the other cases to come up with a a new patch which still handles
the "all fd's are invalid, don't call cygwin_select" correctly...

Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Developer                                mailto:cygwin AT cygwin DOT com
Red Hat, Inc.

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