The scheduling
priority of the process, process group, or user, as indicated by
which
and
who
is obtained with the
getpriority()
system call and set with the
setpriority()
system call.
The
which
argument
is one of
PRIO_PROCESS,
PRIO_PGRP,
or
PRIO_USER,
and
who
is interpreted relative to
which
(a process identifier for
PRIO_PROCESS,
process group
identifier for
PRIO_PGRP,
and a user ID for
PRIO_USER).
A zero value of
who
denotes the current process, process group, or user.
The
prio
argument
is a value in the range -20 to 20.
The default priority is 0;
lower priorities cause more favorable scheduling.
The
getpriority()
system call returns the highest priority (lowest numerical value)
enjoyed by any of the specified processes.
The
setpriority()
system call sets the priorities of all of the specified processes
to the specified value.
Only the super-user may lower priorities.