freebsd-dev/lib/libc/gen/nice.3
Warner Losh fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00

98 lines
2.9 KiB
Groff

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.\" @(#)nice.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd February 28, 2015
.Dt NICE 3
.Os
.Sh NAME
.Nm nice
.Nd set program scheduling priority
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn nice "int incr"
.Sh DESCRIPTION
.Bf -symbolic
This interface is obsoleted by
.Xr setpriority 2 .
.Ef
.Pp
The
.Fn nice
function adds
.Fa incr
to the scheduling priority of the process.
The priority is a value in the range -20 to 20.
The default priority is 0; lower priorities cause more favorable scheduling.
Only the super-user may lower priorities.
.Pp
Children inherit the priority of their parent processes via
.Xr fork 2 .
.Sh RETURN VALUES
Upon successful completion,
.Fn nice
returns 0, and
.Va errno
is unchanged.
Otherwise, \-1 is returned, the process' nice value is not changed, and
.Va errno
is set to indicate the error.
.Sh ERRORS
The
.Fn nice
function will fail if:
.Bl -tag -width Er
.It Bq Er EPERM
The
.Fa incr
argument is negative and the caller does not have appropriate privileges.
.El
.Sh SEE ALSO
.Xr nice 1 ,
.Xr fork 2 ,
.Xr setpriority 2 ,
.Xr renice 8
.Sh STANDARDS
The
.Fn nice
function conforms to
.St -p1003.1-2008
except for the return value.
This implementation returns 0 upon successful completion but
the standard requires returning the new nice value,
which could be \-1.
.Sh HISTORY
A
.Fn nice
syscall appeared in
.At v6 .