time_nanosleep
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.
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 $timestamp
)
Makes the script sleep until the specified timestamp.
Parameters
- timestamp
-
The timestamp when the script should wake.
Return Values
Returns TRUE on success or FALSE on failure.
Changelog
| Version | Description |
|---|---|
| 5.3.0 | This function is now available on Windows platforms. |
Errors/Exceptions
If the specified timestamp is in the past, this function will generate a E_WARNING.
Examples
Example #1 A time_sleep_until() example
<?php
//returns false and generates a warning
var_dump(time_sleep_until(time()-1));
// may only work on faster computers, will sleep up to 0.2 seconds
var_dump(time_sleep_until(microtime(true)+0.2));
?>
Notes
Note: All signals will be delivered after the script wakes up.
See Also
- sleep() - Delay execution
- usleep() - Delay execution in microseconds
- time_nanosleep() - Delay for a number of seconds and nanoseconds
- set_time_limit() - Limits the maximum execution time
add a note
User Contributed Notes
time_sleep_until
purdue at nc dot rr dot com
05-May-2011 11:04
f dot schima at ccgmbh dot de
15-Feb-2010 09:32
Remember when using usleep() as a replacement for time_sleep_until() that usleep() can be interrupted by signals, time_sleep_until() not.
pasha
03-Sep-2009 06:11
To ensure that usleep() is called with the same argument as the one being tested - a positive number:
<?php
if (!function_exists('time_sleep_until')) {
function time_sleep_until($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 07:05
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(($future - microtime(1))*1000000);
return true;
}
}
?>
ssnoyes at hotmail dot com
25-Nov-2005 11:58
Implementation for < 5.1 or Windows users
<?php
if (!function_exists('time_sleep_until')) {
function time_sleep_until($future) {
if ($future < time()) {
trigger_error("Time in past", E_USER_WARNING);
return false;
}
sleep($future - time());
return true;
}
}
?>