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<posix_strerrorposix_times>
^POSIX FunctionsLast updated: Mon, 26 Oct 2026

posix_sysconf

(PHP 8 >= 8.3.0)

posix_sysconf — Returns system runtime information

Description

function posix_sysconf(int $conf_id): int

Returns system runtime information.

Parameters

conf_id

Identifier of the variable with the following constants POSIX_SC_ARG_MAX, POSIX_SC_PAGESIZE, POSIX_SC_NPROCESSORS_CONF, POSIX_SC_NPROCESSORS_ONLN, POSIX_SC_CHILD_MAX, POSIX_SC_CLK_TCK

Return Values

Returns the numeric value related to conf_id

Examples

Example #1 posix_sysconf() example

Returns the number of active cpus.

<?php
echo posix_sysconf(POSIX_SC_NPROCESSORS_ONLN);
?>

The above example will output:

2

<posix_strerrorposix_times>
^POSIX FunctionsLast updated: Mon, 26 Oct 2026