(PHP 4, PHP 5, PHP 7, PHP 8)
usleep — Delay execution in microseconds
$microseconds): voidDelays program execution for the given number of microseconds.
microsecondsHalt time in microseconds. A microsecond is one millionth of a second.
Note: Values larger than
1000000(i.e. sleeping for more than a second) may not be supported by the operating system. Use sleep() instead.
Note: The sleep may be lengthened slightly (i.e. may be longer than
microseconds) by any system activity or by the time spent processing the call or by the granularity of system timers.
No value is returned.
Example #1 usleep() example
<?php
// Current time
echo (new DateTime('now'))->format('H:i:s.v'), "\n";
// wait for 2 milliseconds
usleep(2000);
// back!
echo (new DateTime('now'))->format('H:i:s.v'), "\n";
// wait for 30 milliseconds
usleep(30000);
// back again!
echo (new DateTime('now'))->format('H:i:s.v'), "\n";
?>
The above example will output:
11:13:28.005 11:13:28.007 11:13:28.037