A simple ForkManager

ForkManager.php

<?php

/**
 *
 */
class ForkManager
{
    /**
     * @var array Collection of pids running
     */
    protected $pids = array();
    /**
     * @param $f
     * @param array $parameters parameters to give to the closure function
     * @param bool $wait if the execute have to wait
     * @return bool
     */
    public function execute($f, array $parameters, $wait = true)
    {
        $pid = pcntl_fork();
        if ($pid == -1) {
            new \Exception('Unable to fork current process');
        } else if ($pid) {
            if ($wait) {
                pcntl_wait($status);
            } else {
                $this->pids[$pid] = $pid;
            }
        } else {
            call_user_func_array($f, $parameters);
            exit();
        }
        return true;
    }
    
    public function wait($nbProcessWait = 0)
    {
        if ($nbProcessWait > 0)
            $nbProcessWait -= 1;

        while (count($this->pids) > $nbProcessWait) {
            $myId = pcntl_waitpid(-1, $status);
            if (isset($this->pids[$myId])) {
                unset($this->pids[$myId]);
            }
            usleep(100);
        }
    }

}

/**
 * Usage
 */

class test
{
  public function execute()
  {
    $forkManager = new ForkManager();  
    $count = 10;
    while($i < $count){
        $forkManager->execute(array($this, 'forkFunction'), array(), false);
        //Two fork maximum 
        $forkManager->wait(2);
    }
    //kill processes
    $forkManager->wait();  
  }
  
  public function forkFunction()
  {
    echo 'ok';
  }  
}