Hi!

I have written servers in perl, and the following works for me, to determine whether a socket is closed:

As you said, IO::Select will indicate that the socket can_read, so you'll go ahead and read from it, using sysread. sysread returns the number of bytes that were read, or undef on error, or 0 if end-of-file was reached. That last thing basically means that the socket was closed - or at least, you're not going to read from it anymore. So, your logic will look like the following untested, pseudo-code snippet:

my $bytes_read = $socket->sysread($buf, $max_read_len);

if (not defined $bytes_read)
{
    print "ack!  error on the socket\n";
}
elsif ($bytes_read == 0)
{
    print "the socket was closed\n";
}
else
{
    print "woo hoo!  I read $bytes_read bytes from the socket...\n";
}
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Hope that helps.