PHP：可以在windows上实现定时任务的功能[关闭]

I've got one problem that

$filetime_f = md5(filemtime("path.txt"));sleep(5);
$filetime_n = md5(filemtime("path.txt"));

and when I change content in the path.txt in that 5 seconds,no matter what , it remains the same,please give me a right function

The results of filemtime are cached (see the notes) during one php process. So you have to clear it manually with clearstatcache.

$filetime_f = md5(filemtime("path.txt"));
sleep(5);
clearstatcache();
$filetime_n = md5(filemtime("path.txt"));