Last 5.3 release ever available: PHP 5.3.29 - 5.3 now EOL

time_sleep_until

(PHP 5 >= 5.1.0)

time_sleep_until Make the script sleep until the specified time

Description

bool time_sleep_until ( float $timestamp )

Makes the script sleep until the specified timestamp.

Parameters

timestamp

The timestamp when the script should wake.

Return Values

Returns TRUE on success or FALSE on failure.

Changelog

Version Description
5.3.0 This function is now available on Windows platforms.

Errors/Exceptions

If the specified timestamp is in the past, this function will generate a E_WARNING.

Examples

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(microtime(true)+0.2));

?>

Notes

Note: All signals will be delivered after the script wakes up.

See Also

add a note add a note

User Contributed Notes 3 notes

up
2
purdue at nc dot rr dot com
3 years ago
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.
up
2
rowan dot collins at cwtdigital dot com
2 years ago
Not realising that this function existed, I wrote something similar, but it has the additional facility to specify a minimum pause even if the target time has already been reached, for instance in a processor-intensive loop.

It's in seconds rather than microseconds (it's intended for heavy-duty CLI scripts), but that could easily be changed by using microtime(true) and usleep if greater granularity was required.

<?php
   
/**
     * Pause processing until the specified time, to avoid hammering a DB or service
     *
     * @param int $target_time Timestamp
     * @param int $min_sleep Always sleep for a minimum number of seconds,
     *    even if the target timestamp has already passed.
     *     Default 0, meaning only sleep until the target timestamp is reached.
     *
     * @example <code>
         while ( ! $finished )
         {
             $minimum_start_of_next_loop = time() + $min_secs_per_loop;
            
             # DO STUFF THAT MAY OR MAY NOT TAKE VERY LONG
            
             sleep_until( $minimum_start_of_next_loop, $min_pause_between_loops );
         }
     </code>
     */
   
function sleep_until($target_time, $min_sleep = 0)
    {
       
$time_now = time();
       
       
$time_to_target = $target_time - $time_now;
       
       
// If we've already reached the target time, that's fine
       
if ( $time_to_target <= $min_sleep )
        {
           
// If required, sleep for a bit anyway
           
sleep( $min_sleep );
        }
        else
        {
           
// Sleep for the number of seconds until the target time
           
sleep( $time_to_target );
        }
    }
?>
up
0
roberto at spadim dot com dot br
7 years ago
better implementation
<?php
if (!function_exists('time_sleep_until')) {
   function
time_sleep_until($future) {
       if (
$future < time()) {
          
trigger_error("Time in past", E_USER_WARNING);
           return
false;
       }

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