NAME

nice — set program scheduling priority

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <unistd.h>

int
nice(int incr);

DESCRIPTION

The nice() function obtains the scheduling priority of the process from the system and sets it to the priority value specified in incr. The priority is a value in the range -20 to 20. The default priority is 0; lower priorities cause more favorable scheduling. Only a process with appropriate privileges may lower priorities.

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

RETURN VALUES

Upon successful completion, nice() returns the new nice value minus NZERO. 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), fork(2), setpriority(2), renice(8)

STANDARDS

The nice() function conforms to X/Open Portability Guide Issue 4, Version 2 (“XPG4.2”).

HISTORY

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