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98 lines
2.9 KiB
Groff
98 lines
2.9 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)nice.3 8.1 (Berkeley) 6/4/93
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.\" $FreeBSD$
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.\"
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.Dd February 28, 2015
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.Dt NICE 3
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.Os
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.Sh NAME
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.Nm nice
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.Nd set program scheduling priority
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In unistd.h
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.Ft int
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.Fn nice "int incr"
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.Sh DESCRIPTION
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.Bf -symbolic
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This interface is obsoleted by
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.Xr setpriority 2 .
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.Ef
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.Pp
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The
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.Fn nice
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function adds
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.Fa incr
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to the scheduling priority of the process.
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The priority is a value in the range -20 to 20.
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The default priority is 0; lower priorities cause more favorable scheduling.
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Only the super-user may lower priorities.
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.Pp
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Children inherit the priority of their parent processes via
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.Xr fork 2 .
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.Sh RETURN VALUES
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Upon successful completion,
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.Fn nice
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returns 0, and
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.Va errno
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is unchanged.
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Otherwise, \-1 is returned, the process' nice value is not changed, and
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.Va errno
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is set to indicate the error.
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.Sh ERRORS
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The
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.Fn nice
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EPERM
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The
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.Fa incr
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argument is negative and the caller does not have appropriate privileges.
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.El
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.Sh SEE ALSO
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.Xr nice 1 ,
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.Xr fork 2 ,
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.Xr setpriority 2 ,
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.Xr renice 8
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.Sh STANDARDS
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The
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.Fn nice
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function conforms to
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.St -p1003.1-2008
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except for the return value.
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This implementation returns 0 upon successful completion but
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the standard requires returning the new nice value,
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which could be \-1.
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.Sh HISTORY
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A
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.Fn nice
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syscall appeared in
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.At v6 .
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