#!/usr/bin/perl -w
#preload.pl
use IPC::Shareable;
my $newvalue;
tie $newvalue,'IPC::Shareable','kali',{create => 1,size => 65536};
$newvalue=0;

##</code><code>##

#!/usr/bin/perl -w
#ipcprocesses.pm.
#you may find some of the variables are not defined here
#that is fine for demo purpose.
package ipcprocesses;
use POSIX;
use IPC::Shareable;

my $newvalue;
my $num_children = 0;

sub new {
my $class = shift;
my $this = { 'field' => 1 };
bless ($this,$class);
tie $newvalue,'IPC::Shareable','kali';
return ($this);
}

$SIG{CHLD} = \&DO_AirGREAPER;
$SIG{INT}  = $SIG{TERM} = \&DO_AirGStopHandler;
$SIG{ALRM} = sub {};

sub DO_AirGStopHandler
   {
    local( $SIG{CHLD} ) = 'IGNORE'; 
    kill 'INT' => keys %H_children; 
    exit;
   }

sub DO_AirGREAPER
    {                        # takes care of dead children
     my ( $N_pid );
     # If a second child dies while in the signal handler 
     #caused by the
     # first death, we won't get another signal. So must    
     # loop here else
     # we will leave the unreaped child as a zombie. And the
     # next time
     # two children die we get another zombie. And so on.

while ( ($N_pid = waitpid(-1, &WNOHANG)) > 0 ) {
    if (WIFEXITED $?){
       $num_children--;
    }
}

$SIG{CHLD} = \&DO_AirGREAPER;

}
sub DO_Initprocesspool
   {
    my $this = shift;
    # Fork off our children.
    for ( 1 .. 2 )
       {
        $this->DO_newchild();
       }
   }

sub DO_newchild 
   {
    my $this = shift;
    if ($pid = fork) 
    { #parent
    $this->{'field'} = $newvalue;
    $num_children++;
    print 'parent'.$$.'|'.$this->{'field'}."\n";
    return;
    }
    else{
         my $newvalue;
         tie $newvalue,"IPC::Shareable",'kali';
         #Children can not return from this subroutine
         $SIG{INT} = 'DEFAULT';    #make SIGINT kill us as it did before
          while(1) {
            sleep 2;
            print 'child'.$$.'|'.$this->{'field'}."\n";            
            $newvalue = time();
          }
      }
   exit;
}

sub DO_MaintainPopulation
   {
    my $this = shift;
    for ( my $i = $num_children; $i < 2; $i++ )
     {
      # top up the child pool
      $this->DO_newchild();
     }

}

1;


##</code><code>##

#!/usr/bin/perl -w
#ipcprocesses.pl
use strict;
use lib qw (/somepath);

use ipcprocesses;

my $fork = ipcprocesses->new();

while ( 1 )
     {
      $fork->DO_MaintainPopulation();
     }