<?php
class fork {
  private $children = array();
 
  public function __construct($threads) {
    $this->timestart = microtime(true);
    $this->threads = $threads;
  }
 
  public function forker($worker, $data) {
    foreach($data as $row) {
      $pid = pcntl_fork();
      if($pid == -1 ) {
        exit(1);
      } elseif($pid) {
        echo ' PARENT | launching thread (pid: '.$pid.')'."\n";
        $this->children[] = $pid;
        if(count($this->children) >= $this->threads) {
          $pid = array_shift($this->children);
          pcntl_waitpid($pid, $status);
        }
      } else {
        echo ' CHILD  | working on '.$worker.'('.$row.')'."\n";
        $worker($row);
        echo ' CHILD  | finish '.$worker.'('.$row.')'."\n";
        exit(0);
      }
    }
  }
 
  public function waitchildrens() {
    foreach($this->children as $child) {
      pcntl_waitpid($child, $status);
    }
  }
 
  public function time() {
    $timeend = microtime(true);
    $time = $timeend - $this->timestart;
    echo ' TIME   | '.$time.' seconde(s)'."\n";
  }
}
?>

<?php
$fork = new fork(4);
$fork->forker('test', array('11111111',
                            '22222222',
                            '33333333',
                            '44444444',
                            '55555555',
                            '66666666',
                            '77777777',
                            '88888888'));
$fork->waitchildrens();
$fork->time();
?>