Delay execution in microseconds

# usleep

(PHP 4, PHP 5, PHP 7, PHP 8)

usleep — Delay execution in microseconds

### Description

usleep(int `$microseconds`): void

Delays program execution for the given number of microseconds.

### Parameters

`microseconds`

  Halt 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.

### Return Values

No value is returned.

### Examples

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

### See Also

- sleep() - Delay execution
- time_nanosleep() - Delay for a number of seconds and nanoseconds
- time_sleep_until() - Make the script sleep until the specified time
- set_time_limit() - Limits the maximum execution time

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