pcntl_setpriority

(PHP 5, PHP 7, PHP 8)

pcntl_setpriority — Change the priority of any process

Descripción

pcntl_setpriority(int $priority, ?int $process_id = null, int $mode = PRIO_PROCESS): bool

pcntl_setpriority() sets the priority of process_id.

Parámetros

priority: priority is generally a value in the range -20 to 20. The default priority is 0 while a lower numerical value causes more favorable scheduling. Because priority levels can differ between system types and kernel versions, please see your system's setpriority(2) man page for specific details.
process_id: If null, the process id of the current process is used.
mode: One of PRIO_PGRP, PRIO_USER, PRIO_PROCESS, PRIO_DARWIN_BG or PRIO_DARWIN_THREAD.

Valores devueltos

Devuelve true en caso de éxito o false en caso de error.

Historial de cambios

Versión	Descripción
8.0.0	`process_id` is nullable now.

Ver también

pcntl_getpriority() - Get the priority of any process
pcntl_setpriority()

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User Contributed Notes 2 notes

down

t dot stobbe at blackdogdev dot com ¶

18 years ago

As for the renice function by leandro dot pereira at gmail dot com, this isn't true.  pcntl_setpriority() doesn't set the nice level of a process, but instead sets the base priority of it.  At first glance this might seem like the same thing, but on a system level, they are actually quite different.

In fact, if you're looking to use pcntl_setpriority() to prioritize your process (a tool or a daemon or what-not), I wouldn't recomend using setpriority at all, but renice it instead.  Let the system manage priorities and you'll end up with the results you were looking for.

This applies only to POSIX based systems only (as does the function presented by leandro dot pereira at gmail dot com as well).

down

-1

leandro dot pereira at gmail dot com ¶

19 years ago

The following snippet may be used under older versions of PHP to provide similar functionality.  Tested only under Linux.

<?php
function _pcntl_setpriority($priority, $pid = 0)
{ 
        $priority = (int)$priority;
        $pid = (int)$pid;

        if ($priority > 20 && $priority < -20) {
                return False;
        }
        if ($pid == 0) {
                $pid = getmypid();
        }

        return system("renice  $priority -p $pid") != false;
}

?>

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