nice — change process priority
inc to the nice value for the
calling process. (A higher nice value means a low priority.)
Only the superuser may specify a negative increment, or
priority increase. The range for nice values is described in
On success, the new nice value is returned (but see NOTES
below). On error, −1 is returned, and
errno is set appropriately.
The calling process attempted to increase its
priority by supplying a negative
inc but has insufficient
privileges. Under Linux, the
CAP_SYS_NICE capability is required.
(But see the discussion of the
RLIMIT_NICE resource limit in
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. However, the Linux and (g)libc (earlier than glibc 2.2.4) return value is nonstandard, see below. SVr4 documents an additional EINVAL error code.
SUSv2 and POSIX.1 specify that
nice() should return the new nice value.
However, the Linux system call and the
nice() library function provided in older
versions of (g)libc (earlier than glibc 2.2.4) return 0 on
success. The new nice value can be found using getpriority(2).
Since glibc 2.2.4,
implemented as a library function that calls getpriority(2) to obtain
the new nice value to be returned to the caller. With this
implementation, a successful call can legitimately return
−1. To reliably detect an error, set
errno to 0 before the call, and check its
This page is part of release 4.07 of the Linux
man-pages project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
Copyright (c) 1992 Drew Eckhardt <drewcs.colorado.edu>, March 28, 1992
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.
Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date. The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein. The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
Modified by Michael Haardt <michaelmoria.de>
Modified 1993-07-24 by Rik Faith <faithcs.unc.edu>
Modified 1996-11-04 by Eric S. Raymond <esrthyrsus.com>
Modified 2001-06-04 by aeb
Modified 2004-05-27 by Michael Kerrisk <mtk.manpagesgmail.com>