PHP Manual: Change the priority of the current process

Description

bool proc_nice(int $priority)

proc_nice changes the priority of the current process by the amount specified in priority. A positive priority will lower the priority of the current process, whereas a negative priority will raise the priority.

proc_nice is not related to proc_open and its associated functions in any way.

Parameters

priority

The new priority value, the value of this may differ on platforms.

On Unix, a low value, such as -20 means high priority whereas positive values have a lower priority.

For Windows the priority parameter has the following meaning:

Priority class	Possible values
High priority	`priority` `< -9`
Above normal priority	`priority` `< -4`
Normal priority	`priority` `< 5` & `priority` `> -5`
Below normal priority	`priority` `> 5`
Idle priority	`priority` `> 9`

Return Values

Returns true on success or false on failure. If an error occurs, like the user lacks permission to change the priority, an error of level E_WARNING is also generated.

Changelog

Version	Description
7.2.0	This function is now available on Windows.

Examples

Example #1 Using proc_nice to set the process priority to high

<?php
// Highest priority
proc_nice(-20);
?>

Notes

Note: Availability

proc_nice will only exist if your system has 'nice' capabilities. 'nice' conforms to: SVr4, SVID EXT, AT&T, X/OPEN, BSD 4.3.

Note: Windows only

proc_nice will change the current process priority, even if PHP was compiled using thread safety.

proc_nice