1.\" Copyright (c) 1980, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)nice.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD$ 30.\" 31.Dd February 28, 2015 32.Dt NICE 3 33.Os 34.Sh NAME 35.Nm nice 36.Nd set program scheduling priority 37.Sh LIBRARY 38.Lb libc 39.Sh SYNOPSIS 40.In unistd.h 41.Ft int 42.Fn nice "int incr" 43.Sh DESCRIPTION 44.Bf -symbolic 45This interface is obsoleted by 46.Xr setpriority 2 . 47.Ef 48.Pp 49The 50.Fn nice 51function adds 52.Fa incr 53to the scheduling priority of the process. 54The priority is a value in the range -20 to 20. 55The default priority is 0; lower priorities cause more favorable scheduling. 56Only the super-user may lower priorities. 57.Pp 58Children inherit the priority of their parent processes via 59.Xr fork 2 . 60.Sh RETURN VALUES 61Upon successful completion, 62.Fn nice 63returns 0, and 64.Va errno 65is unchanged. 66Otherwise, \-1 is returned, the process' nice value is not changed, and 67.Va errno 68is set to indicate the error. 69.Sh ERRORS 70The 71.Fn nice 72function will fail if: 73.Bl -tag -width Er 74.It Bq Er EPERM 75The 76.Fa incr 77argument is negative and the caller does not have appropriate privileges. 78.El 79.Sh SEE ALSO 80.Xr nice 1 , 81.Xr fork 2 , 82.Xr setpriority 2 , 83.Xr renice 8 84.Sh STANDARDS 85The 86.Fn nice 87function conforms to 88.St -p1003.1-2008 89except for the return value. 90This implementation returns 0 upon successful completion but 91the standard requires returning the new nice value, 92which could be \-1. 93.Sh HISTORY 94A 95.Fn nice 96syscall appeared in 97.At v6 . 98