# server.pl
use strict;
use IO::Socket;
use IO::Select;

my $main_sock = new IO::Socket::INET(
  LocalAddr => '127.0.0.1',
  LocalPort => 1200,
  Proto     => 'tcp',
  Listen    => 1,
  ReuseAddr => 1,
);

die "Could not initialize server: $!\n"
  unless $main_sock;

print "Server has successfully initialized.\n\n";

my $r_handles = new IO::Select();
$r_handles->add( $main_sock );

while (1) {
  my ($new_r) = IO::Select->select(
    $r_handles, undef, undef, 0
  );

  foreach my $sock (@$new_r) {
    if ($sock == $main_sock) {
      my $new_sock = $sock->accept();
      $r_handles->add($new_sock);
    } else {
      my $buf = <$sock>;
      if ($buf) {
        print "$buf\n";
      } else {
        $r_handles->remove($sock);
        close $sock;
      }
    }
  }

}



# client.pl
use strict;
use IO::Socket;

my $client_id = $ARGV[0];

my $sock = new IO::Socket::INET(
  PeerAddr => '127.0.0.1',
  PeerPort => 1200,
  Proto    => 'tcp',
);

die "Could not connect to server: $!\n"
  unless $sock;

for (1 .. 5) {
  print $sock "From $client_id: Msg $_\n";
  sleep 1;
}

close $sock;
[download]

Okay, so there is no fork() here and it successfully allows multiple clients to be connected at any given time. The problem I've run into is allowing data to flow both ways on the connection. I do know a little bit about sockets (though not nearly as much as I'd like) and know that I will most likely have to setup the second communication line on another port. This would be fine. So what is my guess as to what I would do? More or less mix the two scripts together so that I have one listener and one sender on each side of the connection. The part I just cannot figure out for the life of me is where I would/could/should mix the scripts together. The current server (that receives data from the client) is in an infinite loop, therefore I'd have to send data somewhere within that loop. But where and exactly how? I also understand that if I do end up having 2 connections in each script that I need the IP address for both sides to get things going. But don't worry, I already have a sneeky way to do that.

I have now confused myself to death over this, and I'd really love to discover a solution to this. I've wanted a bi-directional client/server app for a while, but not until today did I find those examples that do not require the use of fork(). Of course, if WIn32 properly supported fork, I would not have to ask this, but you know how things are :) Help!