#!/usr/bin/perl

use strict;
my $MAX_PROCESSES=10;

 my $npids=0;
 for(1..15) {
   my $pid;
   print "Forking: $_\n";
   sleep 1;
   $pid=fork();
   if($pid > 0) { #we forked successfully
        $npids++;
        if($npids>=$MAX_PROCESSES)
        {
                my $wait=wait();
                if($wait) { $npids--; }
        }
        elsif(undef $pid) { # we didn't fork successfully
                print "fork error!\n";
        }
        else { #what do we want to do?
                &doit($_);
                exit(0); # free this pid
        }
        exit(0); # we shouldn't get to this point
   }
  }
  # if we have any stragglers, lets wait for them to finish.
  for(1..$npids){
    my $wt=wait();
   if($wt==-1){
    #print "hey $!\n";
    redo;
   }
  }


sub doit {
        my $num = shift;
        sleep 5;
        print "$num DONE\n";
}