.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved. The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\" @(#)getpriority.2 6.1 (Berkeley) %G%
getpriority, setpriority \- get/set program scheduling priority
#include <sys/resource.h>
#define PRIO_PROCESS 0 /* process */
#define PRIO_PGRP 1 /* process group */
#define PRIO_USER 2 /* user id */
prio = getpriority(which, who)
setpriority(which, who, prio)
priority of the process, process group, or user, as indicated by
is one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER, and
is interpreted relative to
(a process identifier for PRIO_PROCESS, process group
identifier for PRIO_PGRP, and a user ID for PRIO_USER).
is a value in the range \-20 to 20. The default priority is 0;
lower priorities cause more favorable scheduling.
call returns the highest priority (lowest numerical value)
enjoyed by any of the specified processes. The
call sets the priorities of all of the specified processes
to the specified value. Only the super-user may lower priorities.
can legitimately return the value \-1, it is necessary
to clear the external variable \fIerrno\fP prior to the
call, then check it afterward to determine
if a \-1 is an error or a legitimate value.
call returns 0 if there is no error, or
may return one of the following errors:
No process(es) were located using the
was not one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER.
In addition to the errors indicated above,
may fail with one of the following errors returned:
A process was located, but neither its effective nor real user
ID matched the effective user ID of the caller.
A non super-user attempted to change a process
priority to a negative value.
nice(1), fork(2), renice(8)