getpriority(3)          (BSD Compatibility Package)          getpriority(3)


   NAME
         getpriority, setpriority - get/set program scheduling priority

   SYNOPSIS
         cc [ flag... ] file ... -lucb

         #include <sys/time.h>
         #include <sys/resource.h>

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

         int 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 getpriority and set with
         setpriority The default priority is 0; lower priorities cause more
         favorable scheduling.

         which is one of PRIOPROCESS, PRIOPGRP, or PRIOUSER, and who is
         interpreted relative to which (a process identifier for PRIOPROCESS,
         process group identifier for PRIOPGRP, and a user ID for PRIOUSER).
         A zero value of who denotes the current process, process group, or
         user.

         getpriority returns the highest priority (lowest numerical value)
         enjoyed by any of the specified processes.  setpriority sets the
         priorities of all of the specified processes to the value specified
         by prio.  If prio is less than -20, a value of -20 is used; if it is
         greater than 20, a value of 20 is used.  Only the privileged 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 PRIOPROCESS, PRIOPGRP, or PRIOUSER.





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   getpriority(3)          (BSD Compatibility Package)          getpriority(3)


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

         EPERM     A process was located, but one of the following is true:

                   ⊕  Neither its effective nor real user ID matched the
                      effective user ID of the caller, and neither the
                      effective nor the real user ID of the process executing
                      the setpriority was the privileged user.

                   ⊕  The call to getpriority would have changed a process'
                      priority to a value lower than its current value, and
                      the effective user ID of the process executing the call
                      was not that of the privileged user.

   SEE ALSO
         renice(1M).

         nice(1) in the User's Reference Manual.
         fork(2) in the Programmer's Reference Manual.

   NOTES
         It is not possible for the process executing setpriority to lower any
         other process down to its current priority, without requiring
         privileged user privileges.




























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