pcntl_setpriority

(PHP 5, PHP 7, PHP 8)

pcntl_setpriority — Change la priorité d'un processus

Description

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

pcntl_setpriority() change la priorité de process_id à priority.

Liste de paramètres

priority: priority est généralement une valeur allant de -20 à 20. La priorité par défaut est 0 tandis qu'une valeur numérique plus petite favorise une meilleure planification. Comme les niveaux de priorité changent entre les types de systèmes et les versions de kernel, lisez la page de manuel getpriority(2) de votre système pour des détails spécifiques.
process_id: Si null, l'identifiant du processus courant est utilisé.
mode: Une constante parmi PRIO_PGRP, PRIO_USER, PRIO_PROCESS, PRIO_DARWIN_BG ou PRIO_DARWIN_THREAD.

Valeurs de retour

Cette fonction retourne true en cas de succès ou false si une erreur survient.

Historique

Version	Description
8.0.0	`process_id` est désormais nullable.

Voir aussi

pcntl_getpriority() - Retourne la priorité d'un processus
pcntl_setpriority()

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User Contributed Notes 2 notes

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t dot stobbe at blackdogdev dot com ¶

17 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).

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-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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