use strict;
use warnings;

$|=1;

if (fork() == 0) {
   print("$$: Child 1.$/");
   sleep(3);
} elsif (fork() == 0) {
   print("$$: Child 2.$/");
   sleep(3);
} else {
   print("$$: Parent.$/");
   sleep(3);
}

print("$$: oye.$/");

##</code><code>##

use strict;
use warnings;

use IO::Socket::INET;

$|=1;

if (fork() == 0) {
   print("$$: Child 1.$/");
   my $server = IO::Socket::INET->new( 
      Type => SOCK_STREAM, 
      Proto => 'TCP', 
      LocalPort => 2500, 
      Reuse => 1, 
      Listen => 10
   );
   $server->accept();
} else {
   sleep(1);   # Make sure accept is reached.
   if (fork() == 0) {
      print("$$: Child 2.$/");
      sleep(3);
   } else {
      print("$$: Parent.$/");
      sleep(3);
   }
}

print("$$: oye.$/");

##</code><code>##

use strict;
use warnings;

use IO::Socket::INET;

$|=1;

my $server = IO::Socket::INET->new( 
   Type => SOCK_STREAM, 
   Proto => 'TCP', 
   LocalPort => 2500, 
   Reuse => 1, 
   Listen => 10
);

if (fork() == 0) {
   print("$$: Child 1.$/");
   $server->accept();
} else {
   sleep(1);   # Make sure accept is reached.
   if (fork() == 0) {  # <------ Doesn't returns until accept returns.
      print("$$: Child 2.$/");
      sleep(3);
   } else {
      print("$$: Parent.$/");
      sleep(3);
   }
}

print("$$: oye.$/");