1.\" $NetBSD: nice.3,v 1.10 2002/02/07 07:00:15 ross Exp $ 2.\" 3.\" Copyright (c) 1980, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)nice.3 8.1 (Berkeley) 6/4/93 35.\" 36.Dd February 16, 1998 37.Dt NICE 3 38.Os 39.Sh NAME 40.Nm nice 41.Nd set program scheduling priority 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]unistd.h\*[Gt] 46.Ft int 47.Fn nice "int incr" 48.Sh DESCRIPTION 49.Bf -symbolic 50This interface is obsoleted by 51.Xr setpriority 2 . 52.Ef 53.Pp 54The 55.Fn nice 56function obtains the scheduling priority of the process 57from the system and sets it to the priority value specified in 58.Fa incr . 59The priority is a value in the range -20 to 20. 60The default priority is 0; lower priorities cause more favorable scheduling. 61Only the super-user may lower priorities. 62.Pp 63Children inherit the priority of their parent processes via 64.Xr fork 2 . 65.Sh RETURN VALUES 66Upon successful completition, 67.Fn nice 68returns the new nice value minus 69.Dv NZERO . 70Otherwise, -1 is returned, the process' nice value is not changed, and 71.Va errno 72is set to indicate the error. 73.Sh ERRORS 74The 75.Fn nice 76function will fail if: 77.Bl -tag -width Er 78.It Bq Er EPERM 79The 80.Fa incr 81argument is negative and the caller is not the super-user. 82.El 83.Sh SEE ALSO 84.Xr nice 1 , 85.Xr fork 2 , 86.Xr setpriority 2 , 87.Xr renice 8 88.Sh STANDARDS 89The 90.Fn nice 91function conforms to 92.St -xpg4.2 . 93.Sh HISTORY 94A 95.Fn nice 96syscall appeared in 97.At v6 . 98