thr_setprio(3thread)                            thr_setprio(3thread)


       NAME
             thr_setprio - set a thread's scheduling priority

       SYNOPSIS
             cc [options] -Kthread file
             #include <thread.h>
             int thr_setprio(thread_t tid, int prio);

          Parameters
             tid   target thread ID

             prio  priority value for tid

       DESCRIPTION
             thr_setprio sets tid's scheduling priority to be prio.
             thr_setscheduler can also be used to set the priority of a
             thread, but thr_setprio is a shorthand for use when only the
             priority, not the scheduling class, needs to be changed.

             For bound threads, the priority set with thr_setprio is passed
             to the system scheduler; it is not maintained by the Threads
             Library.  For multiplexed threads, the priority set with
             thr_setprio is used by the Threads Library in scheduling
             multiplexed threads to run on LWPs.  The priorities for
             multiplexed threads remain fixed (unless explicitly changed
             with thr_setscheduler or thr_setprio), and the Threads Library
             assigns higher priority threads to LWPs before lower priority
             threads.

          Priority Range for Multiplexed Threads
             In this implementation, the priority range for the SCHED_TS
             policy for multiplexed threads is from zero to MAXINT-1.
             However, for better performance we recommend using a maximum
             priority of 126 or lower.  The default priority for
             multiplexed threads is 63.

             In all scheduling policies supported by this implementation,
             numerically higher values represent higher priorities.

          Priority Range for Bound Threads
             Bound threads running under any scheduling policy are subject
             to the priority ranges set by the system.  Use priocntl(1) or
             priocntl(2) to find what scheduling priorities are available
             on your system.




                           Copyright 1994 Novell, Inc.               Page 1

      thr_setprio(3thread)                            thr_setprio(3thread)


         Security Restrictions
            No privileges or special permissions are required to use
            thr_setprio to set the priority of a multiplexed thread.  The
            following rules apply to changing the priority of bound
            threads:

                  You can always lower the priority of any bound thread.

                  You can always raise the priority of bound threads in
                  the SCHED_FIFO and SCHED_RR classes.

                  You must have privilege to raise the priority of a bound
                  thread in the SCHED_TS class.  The required privileges
                  may vary across installations.

         Return Values
            thr_setprio returns zero for success and an error number for
            failure, as described below.

         Errors
            If any of the following error conditions is detected,
            thr_setprio fails and returns the corresponding value:

            EINVAL   The value of prio is invalid for tid's current
                     scheduling policy.

            EPERM    The caller does not have appropriate privilege to set
                     the priority of tid.

            ESRCH    No thread with identifier tid can be found in the
                     process.

      REFERENCES
            priocntl(2), thr_getprio(3thread), thr_getscheduler(3thread),
            thr_setscheduler(3thread), thr_yield(3thread), thread(3thread)













                          Copyright 1994 Novell, Inc.               Page 2