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

NAME
     getpriority, setpriority - get/set program scheduling priority

SYNOPSIS
     /usr/ucb/cc [flag ...] file ... -lucb

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

     int getpriority(int which, idt who);

     int setpriority(int which, idt who, int 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.

     The default prio is 0; negative priorities cause more favorable
     scheduling. While the range of valid priority values is [-20, 20],
     implementations may enforce more restrictive limits. If the value
     specified to setpriority() is less than the system's lowest supported
     priority value, the system's lowest supported value is used; if it is
     greater than the system's highest supported value, the system's
     highest supported value is used.

     Only a process with appropriate privileges can raise its priority
     (i.e. assign a lower numerical priority value).

RETURN VALUE
     Since getpriority can legitimately return the value -1, it is neces-
     sary 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 speci-
               fied.

     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 effec-
                  tive 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.

     EACCES    A request was made to change the priority to a lower numeric
               value (that is, to a higher priority) and the current pro-
               cess does not have appropriate privileges.

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

SEE ALSO
     nice(1), renice(1-ucb), fork(2), resource(5), time(5).




























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