(PHP 5 >= 5.1.0)
time_sleep_until — Make the script sleep until the specified time
Makes the script sleep until the specified timestamp .
The timestamp when the script should wake.
如果成功则返回 TRUE，失败则返回 FALSE。
If the specified timestamp is in the past, this function will generate a E_WARNING.
Example#1 A time_sleep_until() example
<?php
//returns false and generates a warning
var_dump(time_sleep_until(time()-1));
// may only work on faster computers, will sleep up to 0.2 seconds
var_dump(time_sleep_until(time()+0.2));
?>
Note: All signals will be delivered after the script wakes up.
Note: 本函数未在 Windows 平台下实现。