hrtime()

hrtime() — Get the system's high resolution time.

Built-in function of PHP 8.5. The manual lists it as available in PHP 7 >= 7.3.0, PHP 8. This page is the reference card: signature, parameters and return value, plus the changelog and the example the manual provides.

What it does

Returns the system's high resolution time, counted from an arbitrary point in time. The delivered timestamp is monotonic and can not be adjusted.

Signature

hrtime(bool $as_number = false): array|int|float|false

Parameters

ParameterTypeWhat it takes
$as_numberboolWhether the high resolution time should be returned as array or number.

Return value

Returns an array of integers in the form [seconds, nanoseconds], if the parameter as_number is false. Otherwise the nanoseconds are returned as int (64bit platforms) or float (32bit platforms). Returns false on failure.

Example

A runnable snippet:

echo hrtime(true), PHP_EOL; print_r(hrtime());

Output:

10444739687370679 Array ( [0] => 10444739 [1] => 687464812 )

Changelog

VersionChange
8.5.0On macOS, the implementation now uses clock_gettime_nsec_np(CLOCK_UPTIME_RAW) instead of mach_absolute_time().

See also

microtime(), time_nanosleep()

All PHP 8.5 built-in functions

Reference card built from the PHP manual page hrtime() (PHP documentation, CC BY 3.0). The page is generated from the manual, so the wording of the parameter and return value text follows php.net.