---
name: "setpriority"
section: "2freebsd"
platform: "linux"
package: "freebsd-manpages"
version: "12.2-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/getpriority/2freebsd"
---

# setpriority(2freebsd)

get/set program scheduling priority

Part of [getpriority(2freebsd)](/getpriority/2freebsd.md).

## NAME

**getpriority**, **setpriority** – get/set program scheduling priority

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<sys/time.h\>**

**#include \<sys/resource.h\>**

*int*\

**getpriority**(*int which*, *int who*);

*int*\

**setpriority**(*int which*, *int who*, *int prio*);

## DESCRIPTION

The scheduling priority of the process, process group, or user, as indicated by *which* and *who* is obtained with the **getpriority**() system call and set with the **setpriority**() system call. The *which* argument is one of PRIO\_PROCESS, PRIO\_PGRP, or PRIO\_USER, and *who* is interpreted relative to *which* (a process identifier for PRIO\_PROCESS, process group identifier for PRIO\_PGRP, and a user ID for PRIO\_USER). A zero value of *who* denotes the current process, process group, or user. The *prio* argument is a value in the range -20 to 20. The default priority is 0; lower priorities cause more favorable scheduling.

The **getpriority**() system call returns the highest priority (lowest numerical value) enjoyed by any of the specified processes. The **setpriority**() system call sets the priorities of all of the specified processes to the specified value. Only the super-user may lower priorities.

## RETURN VALUES

Since **getpriority**() can legitimately return the value -1, it is necessary to clear the external variable *errno* prior to the call, then check it afterward to determine if a -1 is an error or a legitimate value.

The **setpriority()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## ERRORS

The **getpriority**() and **setpriority**() system calls will fail if:

- \[ESRCH\]

  No process was located using the *which* and *who* values specified.

- \[EINVAL\]

  The *which* argument was not one of PRIO\_PROCESS, PRIO\_PGRP, or PRIO\_USER.

In addition to the errors indicated above, **setpriority**() will fail if:

- \[EPERM\]

  A process was located, but neither its effective nor real user ID matched the effective user ID of the caller.

- \[EACCES\]

  A non super-user attempted to lower a process priority.

## SEE ALSO

[nice(1)](/nice/1.md), [fork(2)](/fork/2.md), [renice(8)](/renice/8.md)

## HISTORY

The **getpriority**() system call appeared in 4.2BSD.