php实现多进程 多任务的一例代码

/**
*基于PHP5实现
*借助proc_open
*能启动多进程，你可以使用你的想象力做你想做的了
*如果你是在linux上跑php，并且启用pcntl模块后，使用pcntl函数该更好
*最后修改：by bbs.it-home.org 2013/6/20
**/
    error_reporting(E_ALL);
    set_time_limit(0);
    class Thread {
    protected $_pref; // process reference
    protected static $_instance = null;
    protected $_pipes;
    private function __construct() {
    $this->_pref = 0;
    }
    public static function getInstance($file) {
    if (null == self::$_instance) {
    self::$_instance = new self;
    }
    $descriptor = array(
    0 => array("pipe", "r"),
    1 => array("pipe", "w"),
    2 => array("file", "./error-output.txt", "a"),
    );
    self::$_instance->_pref = proc_open("php -q $file", $descriptor, self::$_instance->_pipes);
    return true;
    }
    public function __destruct() {
    proc_close($this->_pref);
    $this->_pref = null;
}
?>