PHP创建单例后台进程的方法示例

$command = " php script.php ";$pid = exec("nohup $command > /dev/null 2>&1 & echo $!");

//query the database for process id$query = "SELECT pid FROM `daemons` WHERE `pid` = '2013' LIMIT 1";$result = mysql_query($query);$pid = mysql_result($result, 0, 'pid');//check if the process is runningexec("ps $pid", $pState);if((count($pState) >= 2) && !empty($pid)){echo "RUNNING";}else{echo "INACTIVE";}

//check if the process from the database is runningexec("ps $pid", $pState);if((count($pState) >= 2)){//if the process is running, kill itexec("kill $pid");//update database row with an empty process id}