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Date: Mon, 24 Feb 2003 22:42:14 +0100
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: connect() not interrupted by sigalrm?
Message-ID: <20030224214214.GF1677@cygbert.vinschen.de>
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References: <200302241757 DOT h1OHvQN16044 AT head-cfa DOT cfa DOT harvard DOT edu>
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On Mon, Feb 24, 2003 at 12:57:26PM -0500, Eric Mandel wrote:
> 
> Cygwin version:		1.3.20-1
> Win OS tested:		NT 4.0/SP6 and XP
> 
> I have an application that calls alarm() before connect() in order to
> prevent connect() from hanging if the host is down or non-existent.
> When alarm() goes off, it sends the SIGALRM signal, which interrupts
> the connect() system call.  This works under Linux, Solaris, OSF, and
> Mac OS X, but apparently not under Cygwin. As shown in the appended
> code, the alarm does go off and can trigger an associated alarm
> function, but the connect() system call is not interrupted.

The Cygwin connect() call isn't interruptible so far.  It's still
implemented by just calling the WinSock connect() plus some magical
hocus-pocus afterwards.  It's possible to change it to an interruptible
call but that requires some coding.

In the meantime, how about using a non-blocking connect() and a call to
select() instead?

Corinna

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

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