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Date: Tue, 9 Jan 2001 23:41:13 +0100
From: Corinna Vinschen <cygwin AT cygwin DOT com>
To: cygwin <cygwin AT cygwin DOT com>
Subject: Re: Winsock Bug Workaround - closing windows sockets
Message-ID: <20010109234113.I4141@cobold.vinschen.de>
Mail-Followup-To: cygwin <cygwin AT cygwin DOT com>
References: <001801c07b31$d72a4720$904bb4ca AT private>
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In-Reply-To: <001801c07b31$d72a4720$904bb4ca@private>; from david@rebirthing.co.nz on Wed, Jan 10, 2001 at 10:19:14AM -0800

On Wed, Jan 10, 2001 at 10:19:14AM -0800, David McNab wrote:
> #ifdef __CYGWIN__
> int client_sock_flags;
> struct linger lingeropt;
> 
> /* flush out the client socket - set it to blocking, then write to it */
> client_sock_flags=fcntl(client,F_GETFL,0);
> if(client_sock_flags!=-1)
>     /* enable blocking */
>     fcntl(client,F_SETFL,client_sock_flags & ~O_NONBLOCK);
> 
> /* sent it a byte - guaranteed to block - ensure delivery of prior data */
> /* yeah - this is a bit paranoid - try without this at first */
> /* write(client, "\n", 1); */
> 
> /* this is the guts of the workaround for Winsock close bug */
> shutdown(client, 1);
> 
> /* enable lingering */
> lingeropt.l_onoff = 1;
> lingeropt.l_linger = 15;
> setsockopt(client, SOL_SOCKET, SO_LINGER, &lingeropt, sizeof(lingeropt));
> #endif
> 
> /* Winsock bug averted - now we're safe to close the socket */
> close(client);

Weeks ago I tried to implement something similar in
fhandler_socket::close() itself to get rid of that problem
but without luck. This is a good solution for applications
but it's not generalizable, unfortunately.

Corinna

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

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