GETPRIORITY(2)							System Calls Manual						    GETPRIORITY(2)

NAME

       getpriority, setpriority - get/set program scheduling priority

SYNOPSIS

       #include <sys/resource.h>

       prio = getpriority(which, who)
       int prio, which, who;

       setpriority(which, who, prio)
       int which, who, prio;

DESCRIPTION

       The scheduling priority of the process, process group, or user, as indicated by which and who is obtained with the getpriority call and set
       with the setpriority call.  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; lower priorities cause more favorable
       scheduling.

       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 priorities.

RETURN VALUE

       Since 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.

ERRORS

       Getpriority and setpriority may return one of the following errors:

       [ESRCH]	      No process was located using the which and who values specified.

       [EINVAL]       Which was not one of PRIO_PROCESS, PRIO_PGRP, or PRIO_USER.

       In addition to the errors indicated above, setpriority may fail with one of the following errors returned:

       [EPERM]	      A process was located, but neither its effective nor real user ID matched the effective user ID of the caller.

       [EACCES]       A non super-user attempted to lower a process priority.

SEE ALSO

       nice(1), fork(2), renice(8)

4th Berkeley Distribution					   May 22, 1986 						    GETPRIORITY(2)