GETPRIORITY(2)	    UNIX Programmer's Manual	   GETPRIORITY(2)


NAME
     getpriority, setpriority - get/set program scheduling prior-
     ity

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


Printed 11/26/99	  May 22, 1986				1


GETPRIORITY(2)	    UNIX Programmer's Manual	   GETPRIORITY(2)


		    effective nor real user ID matched the effec-
		    tive user ID of the caller.

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

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


Printed 11/26/99	  May 22, 1986				2


 
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