146 lines
4.1 KiB
Groff
146 lines
4.1 KiB
Groff
.\" Copyright (c) 1980, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 3. All advertising materials mentioning features or use of this software
|
|
.\" must display the following acknowledgement:
|
|
.\" This product includes software developed by the University of
|
|
.\" California, Berkeley and its contributors.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)getpriority.2 8.1 (Berkeley) 6/4/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 4, 1993
|
|
.Dt GETPRIORITY 2
|
|
.Os BSD 4
|
|
.Sh NAME
|
|
.Nm getpriority ,
|
|
.Nm setpriority
|
|
.Nd get/set program scheduling priority
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/time.h>
|
|
.Fd #include <sys/resource.h>
|
|
.Ft int
|
|
.Fn getpriority "int which" "int who"
|
|
.Ft int
|
|
.Fn setpriority "int which" "int who" "int prio"
|
|
.Sh DESCRIPTION
|
|
The scheduling
|
|
priority of the process, process group, or user, as indicated by
|
|
.Fa which
|
|
and
|
|
.Fa who
|
|
is obtained with the
|
|
.Fn getpriority
|
|
call and set with the
|
|
.Fn setpriority
|
|
call.
|
|
.Fa Which
|
|
is one of
|
|
.Dv PRIO_PROCESS ,
|
|
.Dv PRIO_PGRP ,
|
|
or
|
|
.Dv PRIO_USER ,
|
|
and
|
|
.Fa who
|
|
is interpreted relative to
|
|
.Fa which
|
|
(a process identifier for
|
|
.Dv PRIO_PROCESS ,
|
|
process group
|
|
identifier for
|
|
.Dv PRIO_PGRP ,
|
|
and a user ID for
|
|
.Dv PRIO_USER ) .
|
|
A zero value of
|
|
.Fa who
|
|
denotes the current process, process group, or user.
|
|
.Fa Prio
|
|
is a value in the range -20 to 20. The default priority is 0;
|
|
lower priorities cause more favorable scheduling.
|
|
.Pp
|
|
The
|
|
.Fn getpriority
|
|
call returns the highest priority (lowest numerical value)
|
|
enjoyed by any of the specified processes. The
|
|
.Fn setpriority
|
|
call sets the priorities of all of the specified processes
|
|
to the specified value. Only the super-user may lower priorities.
|
|
.Sh RETURN VALUES
|
|
Since
|
|
.Fn getpriority
|
|
can legitimately return the value -1, it is necessary
|
|
to clear the external variable
|
|
.Va errno
|
|
prior to the
|
|
call, then check it afterward to determine
|
|
if a -1 is an error or a legitimate value.
|
|
The
|
|
.Fn setpriority
|
|
call returns 0 if there is no error, or
|
|
-1 if there is.
|
|
.Sh ERRORS
|
|
.Fn Getpriority
|
|
and
|
|
.Fn setpriority
|
|
will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ESRCH
|
|
No process was located using the
|
|
.Fa which
|
|
and
|
|
.Fa who
|
|
values specified.
|
|
.It Bq Er EINVAL
|
|
.Fa Which
|
|
was not one of
|
|
.Dv PRIO_PROCESS ,
|
|
.Dv PRIO_PGRP ,
|
|
or
|
|
.Dv PRIO_USER .
|
|
.El
|
|
.Pp
|
|
.Bl -tag -width Er
|
|
In addition to the errors indicated above,
|
|
.Fn setpriority
|
|
will fail if:
|
|
.It Bq Er EPERM
|
|
A process was located, but neither its effective nor real user
|
|
ID matched the effective user ID of the caller.
|
|
.It Bq Er EACCES
|
|
A non super-user attempted to lower a process priority.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr nice 1 ,
|
|
.Xr fork 2 ,
|
|
.Xr renice 8
|
|
.Sh HISTORY
|
|
The
|
|
.Fn getpriority
|
|
function call appeared in
|
|
.Bx 4.2 .
|