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.\" 3. 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.Dd February 28, 2015 29.Dt NICE 3 30.Os 31.Sh NAME 32.Nm nice 33.Nd set program scheduling priority 34.Sh LIBRARY 35.Lb libc 36.Sh SYNOPSIS 37.In unistd.h 38.Ft int 39.Fn nice "int incr" 40.Sh DESCRIPTION 41.Bf -symbolic 42This interface is obsoleted by 43.Xr setpriority 2 . 44.Ef 45.Pp 46The 47.Fn nice 48function adds 49.Fa incr 50to the scheduling priority of the process. 51The priority is a value in the range -20 to 20. 52The default priority is 0; lower priorities cause more favorable scheduling. 53Only the super-user may lower priorities. 54.Pp 55Children inherit the priority of their parent processes via 56.Xr fork 2 . 57.Sh RETURN VALUES 58Upon successful completion, 59.Fn nice 60returns 0, and 61.Va errno 62is unchanged. 63Otherwise, \-1 is returned, the process' nice value is not changed, and 64.Va errno 65is set to indicate the error. 66.Sh ERRORS 67The 68.Fn nice 69function will fail if: 70.Bl -tag -width Er 71.It Bq Er EPERM 72The 73.Fa incr 74argument is negative and the caller does not have appropriate privileges. 75.El 76.Sh SEE ALSO 77.Xr nice 1 , 78.Xr fork 2 , 79.Xr setpriority 2 , 80.Xr renice 8 81.Sh STANDARDS 82The 83.Fn nice 84function conforms to 85.St -p1003.1-2008 86except for the return value. 87This implementation returns 0 upon successful completion but 88the standard requires returning the new nice value, 89which could be \-1. 90.Sh HISTORY 91A 92.Fn nice 93syscall appeared in 94.At v6 . 95