$pids = array();$child_pid = pcntl_fork();if ($child_pid == -1){    throw new Exception( __METHOD__ . "|" . __LINE__ .            ": fork() error");}else if ($child_pid){    //parent     exit(0);}else{    //child    for($i=0;$i<3;$i++)    {        $child_pid = pcntl_fork();        if($child_pid)        {            //parent            $pids[] = $child_pid;            sleep(5);            print_r($pids);echo "\n";        }else{            //child            break;        }    }}while(1){     //your code    sleep(1);}