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time_sleep_until

(PHP 5 >= 5.1.0)

time_sleep_until — 使脚本睡眠到指定的时间为止。

说明

bool time_sleep_until ( float $timestamp )

使脚本睡眠到指定的 timestamp。

参数

timestamp

将脚本唤醒的时间戳。

返回值

成功时返回 TRUE， 或者在失败时返回 FALSE.

更新日志

版本 说明
5.3.0 自此，函数在Windows平台可用。

错误/异常

如果设定的 timestamp 为过去的时间，脚本将会产生一个 E_WARNING 级别的错误。

范例

Example #1 time_sleep_until() 的一个例子

<?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(microtime(true)+0.2));

?>

注释

Note: 所有的信号会被延迟至脚本唤醒以后。

参见

杂项 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: 使脚本睡眠到指定的时间为止。

用户评论:

purdue at nc dot rr dot com (05-May-2011 07:04)

At least on my Windows machine, the time_sleep_until function appears to calculate the number of microseconds between now and the sleep-until timestamp, and it appears to use unsigned 32-bit math in this calculation.  This roundoff leads to a maximum sleep time of just under 4295 seconds (1 hour, 11 minutes, 35 seconds).  To get longer sleep times, while still using time_sleep_until to minimize processor overhead, the following loop may be some help to you:

<?php

$sleepuntil = strtotime("tuesday 3pm");

while (time() < $sleepuntil)
   time_sleep_until($sleepuntil);

// proceed with dated processing

?>

Of course, one could use something like "cron" instead, to avoid the script doing the extended sleep.  Also note that time_nanosleep appears to do similar math, but it is somewhat more intuitive that the seconds parameter has an upper limit on what it can be.  Still, both functions might report a warning when waking up prematurely due to roundoff.

f dot schima at ccgmbh dot de (15-Feb-2010 05:32)

Remember when using usleep() as a replacement for time_sleep_until() that usleep() can be interrupted by signals, time_sleep_until() not.

pasha (03-Sep-2009 02:11)

To ensure that usleep() is called with the same argument as the one being tested - a positive number:

<?php
if (!function_exists('time_sleep_until')) {
   function time_sleep_until($future) {
       $sleep = ($future - microtime(1))*1000000;
       if ($sleep<=0) {
           trigger_error("Time in past", E_USER_WARNING);
           return false;
       }

       usleep($sleep);
       return true;
   }
}
?>

roberto at spadim dot com dot br (16-Dec-2006 03:05)

better implementation
<?php
if (!function_exists('time_sleep_until')) {
   function time_sleep_until($future) {
       if ($future < time()) {
           trigger_error("Time in past", E_USER_WARNING);
           return false;
       }

       usleep(($future - microtime(1))*1000000);
       return true;
   }
}
?>

ssnoyes at hotmail dot com (25-Nov-2005 07:58)

Implementation for < 5.1 or Windows users

<?php
if (!function_exists('time_sleep_until')) {
    function time_sleep_until($future) {
        if ($future < time()) {
            trigger_error("Time in past", E_USER_WARNING);
            return false;
        }

        sleep($future - time());
        return true;
    }
}
?>