CloseSocket() problem

Robert Collins
Wed Jan 3 22:32:00 GMT 2001

    I suspect you are seeing an issue that is TCP/IP spec related, not cygwin related. (I have squid 2.4 running on cygwin in
several locations, without any sign of the symptoms you have). However your symptoms sound similar to those faced by Apache and
Squid with half closed connections. Due to tcp/ip's close sequence, and also to general delay between send and acknowledgement of
receipt, you cannot know that the browser has receieved the data just because you have written it to the socket.

Apache used a technique called lingering closes to solve this. You might consider looking into that.

On the other hand I could be completely off base here :-]


----- Original Message -----
From: "David McNab" <>
To: <>
Cc: "Andrew M. Bishop" <>
Sent: Friday, January 05, 2001 12:54 PM
Subject: CloseSocket() problem

> Hi Corinna,
> On searching through Cygwin mail archives, I note that you've had problems
> with closing down sockets in child processes.
> I have experienced the same thing. I'm presently working on testing the
> Win32 Cygwin port of another developer's proxy server program (called
> WWWOFFLE, see ).
> On re-compiling the program with the cygwin v1.1.7.1 dll, I noticed
> Microsoft Internet Explorer complaining that the server connections had been
> reset.
> I have added code to the applicable child process which fcntl()'s the client
> socket to blocking mode, then writes a byte of data. This is an attempt to
> ensure that all data send()'ed to Internet Explorer has actually been sent
> prior to the CloseSocket(). This hack seems to improve things dramatically,
> but the problem still shows when sending larger volumes of data back to
> Internet Explorer.
> Can you please advise on the status of this CloseSocket() problem, and
> 1) Any suggestions for a workaround, and/or
> 2) Whether there are any interim fixes available
> Kindest thanks in advance
> David McNab
> --
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