php文件锁

	//提交加锁lock
	$goldlock = dirname(dirname(dirname(__FILE__))).‘/cache/gold.lock‘;
	while (file_exists($goldlock)) {
		$goldlock_time = @filemtime($goldlock);
		if ($goldlock_time && (time()-$goldlock_time >=5)) {
			@unlink($goldlock);
		}
             　　usleep(rand(100, 500));
        }
        touch($goldlock);

       # 业务代码...

       @unlink($goldlock);//释放锁