#!/usr/bin/perl -w        
use strict;           

use IO::Socket;
use POSIX ":sys_wait_h";

my $RW_BUF_LEN = 256;
my $SERVER_TIMEOUT_SECS = 20;
my $active;

# note SOMAXCONN is system max of queue for incoming clients
# Listen=>1 in this app would have also have been just fine

$SIG{PIPE} = sub {close $active; exit (3)};
$SIG{ALRM} = sub {close $active; exit (7)};
$SIG{CHLD} = sub {local ($!, $?); 
                  while (waitpid(-1, WNOHANG) > 0){} };

my $passive = IO::Socket::INET->new( Proto     => 'tcp',
                                     LocalPort => 12455,
                                     Listen    => SOMAXCONN,
                                     Reuse     => 1,
                                     Type      => SOCK_STREAM
                                   )
     or die "Server is unable to start: $!\n";

while(1)
{
    $active = $passive->accept() or next; #blocking "wait"
           # next not really necessary
           # Perl > 5.8 has deferred signals by default on
           # so a signal cannot occur within accept()!
           # but safety is a good thing!

    die "Bad Fork! $!\n" if ( !defined(my $pid = fork()) );
    
    if ($pid != 0)     # Parent,  Note: Windows has a negative $pid 
                       # (fork emulation)
    {
       close $active;  #parents do not talk to anybody
       next;
    }
    
    ####### we are the child #########
    close $passive;  #Client's don't listen for connections!
    
    #### blah whatever the child does.....
    ## it "talks" on the $active socket's filehandle
 }