(PHP 5, PHP 7, PHP 8)
proc_nice — Change the priority of the current process
$priority): bool
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.
priorityThe 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
|
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.
| Version | Description |
|---|---|
| 7.2.0 | This function is now available on Windows. |
Example #1 Using proc_nice() to set the process priority to high
<?php
// Highest priority
proc_nice(-20);
?>
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.