---
name: "nice"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd", "macos"]
url: "https://new.carta.tech/nice/3"
---

# nice(3)

set program scheduling priority

## NAME

**nice** – set program scheduling priority

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<unistd.h\>**

*int*\

**nice**(*int incr*);

## DESCRIPTION

This interface is obsoleted by [setpriority(2)](/setpriority/2.md).

The **nice**() function adds *incr* to the scheduling priority of the process. The priority is a value in the range -20 to 20. The default priority is 0; lower priorities cause more favorable scheduling. Only the super-user may lower priorities.

Children inherit the priority of their parent processes via [fork(2)](/fork/2.md).

## RETURN VALUES

Upon successful completion, **nice**() returns 0, and *errno* is unchanged. Otherwise, -1 is returned, the process' nice value is not changed, and *errno* is set to indicate the error.

## ERRORS

The **nice**() function will fail if:

- \[EPERM\]

  The *incr* argument is negative and the caller does not have appropriate privileges.

## SEE ALSO

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

## STANDARDS

The **nice**() function conforms to IEEE Std 1003.1-2008 (“POSIX.1”) except for the return value. This implementation returns 0 upon successful completion but the standard requires returning the new nice value, which could be -1.

## HISTORY

A **nice**() syscall appeared in Version 6 AT&T UNIX.