| GETPRIORITY(2) | System Calls Manual | GETPRIORITY(2) | 
getpriority, setpriority
  —
#include <sys/resource.h>
int
  
  getpriority(int
    which, id_t
  who);
int
  
  setpriority(int
    which, id_t who,
    int prio);
getpriority() call and set with the
  setpriority() call.
The priority is maintained in a per-process basis and affects
    scheduling of LWPs which belong to the process and use the
    SCHED_OTHER scheduling class.
which 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. prio is a value in the range -20 to 20. The
    default priority is 0; numerically lower priority values cause more
    favorable scheduling. A value of 19 or 20 will schedule a process only when
    nothing at priority ≤ 0 is runnable.
The getpriority() call returns the highest
    priority (lowest numerical value) enjoyed by any of the specified processes.
    The setpriority() call sets the priorities of all of
    the specified processes to the specified value. Only the super-user may
    lower priority values.
getpriority() can legitimately return the value
  -1, it is necessary to clear the external variable errno
  prior to the call, then check it afterward to determine if a -1 is an error or
  a legitimate value. The setpriority() call returns 0
  if there is no error, or -1 if there is.
getpriority() and setpriority()
  will fail if:
EINVAL]PRIO_PROCESS, PRIO_PGRP,
      or PRIO_USER.ESRCH]In addition to the errors indicated above,
    setpriority() will fail if:
getpriority() function call appeared in
  4.2BSD.
| April 13, 2012 | NetBSD 10.0 |