hrtime
Returns a high-resolution timer reading in nanoseconds.
Syntax
hrtime(bool $as_number = false): array|int|float|falseParameters
| Parameter | Type | Description |
|---|---|---|
| $as_number | bool | Optional. `true` returns a single number. |
Return value
array|int|float|falseThe number of nanoseconds, or an array of seconds and nanoseconds.
Examples
Measuring execution time:
<?php
$start = hrtime(true);
$sum = array_sum(range(1, 100000));
$ms = (hrtime(true) - $start) / 1e6;
echo $sum, ' in ', round($ms, 2), ' ms';Notes
The timer is unaffected by system clock changes, so it is more reliable for measurements than microtime().
See also
- microtime — Returns the current time with microsecond precision.
- time — Returns the current timestamp.
- memory_get_usage — Returns the amount of memory the program uses.
Related recipes
In the tutorial
- Date and time — Working with dates in PHP — the date function, the DateTimeImmutable class, formats, adding to dates and the difference between them.