Subject: Re: Possible problems in select() under Win95/98/ME
From: "Ehud Karni" <[email-masked]>
To: [email-masked]
Cc: [email-masked]
Date: Wed, 31 Jan 2001 17:17:14 +0200

On Wed, 31 Jan 2001 21:34:37 +1000, Vic Cross
    <[email-masked]> wrote:
> 
> The usual process of building a file descriptor set (containing the
> file descriptors for the listener socket and any connected clients)
> and entering a blocking select() call works flawlessly under Linux,
> but under Cygwin the select() appears to ignore the connected clients 
> -- that is, select() does not unblock for incoming data on a client, 
> and a new connection must be initiated to force select() to unblock
 [snip]

I have written a small proxy that use blocking select() and it works
fine on W95/98 (not checked on ME). I've checked ssh and it is also
working with blocking select (it is in packet.c). So, at least in some
cases, select() is working on W95/98.

> This workaround uncovered another problem in select() -- every time
> select() returns, a TCP loopback connection is created and sits in
> TIME_WAIT status until it ages out.  Various methods and tests have
> shown that the spurious connection is *definitely* co-incident with
> the return from select().

I checked with netstat (on W95) and there seems to be some (2 to 4)
loopback connections created. I never so more than 4 connections.

As it happens I had time-out in my proxy for the select(), set to 30
seconds, I changed it to 1 and 3 second and ran my proxy. There seem
to be loopback connection created for each select() return. Then I had
some net activity (not related to the proxy or Cygwin) and the creation
of the loopback connection CEASED !. I then changed the time-out to
300 milliseconds, and no loopback connection was created.

Ehud.

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