NICE(3) | Library Functions Manual | NICE(3)

# NAME

`nice` — change process scheduling priority

# SYNOPSIS

`#include <unistd.h>`

int
`nice`(int incr);

# DESCRIPTION

This interface is obsoleted by setpriority(2).

The `nice`() function adds the value specified in incr to the scheduling priority of the invoking process.

incr is an integer such that the resulting scheduling priority is within the range -20 to 20. Priority values outside this range are truncated to the appropriate limit. The default priority is 0; lower priorities cause more favorable scheduling. Only the superuser may lower priorities.

Children inherit the priority of their parent processes via fork(2).

# RETURN VALUES

On success, `nice`() returns the new priority. On error, it returns -1.

Since `nice`() 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.

# ERRORS

`nice`() has the same failure conditions as setpriority(2).

# SEE ALSO

nice(1), fork(2), setpriority(2), renice(8)

# HISTORY

A `nice`() system call first appeared in Version 3 AT&T UNIX. It has accepted an incr argument since Version 4 AT&T UNIX.

July 18, 2013 | Debian