nice(2)                                                      nice(2)


       NAME
             nice - change priority of a time-sharing process

       SYNOPSIS
             #include <unistd.h>
             int nice(int incr);

       DESCRIPTION
             nice allows a member of the time-sharing scheduling class to
             change its priority.

             nice adds the value of incr to the nice value of the calling
             process.  The nice value is a non-negative number for which a
             more positive value results in lower CPU priority.

             A maximum nice value of 39 and a minimum nice value of 0 are
             imposed by the system.  (The default nice value is 20.)
             Requests for values above or below these limits result in the
             nice value being set to the corresponding limit.

          Return Values
             On success, nice returns the new nice value minus 20.  On
             failure, nice returns -1 and sets errno to identify the error.

          Errors
             In the following conditions, nice fails and sets errno to:

             EPERM         incr is negative or greater than 39 and the
                           effective user ID of the calling process does
                           not have the appropriate privilege.  (P_TSHAR)

             EINVAL        The process was in a scheduling class other than
                           time-sharing.

       USAGE
             priocntl(2) is a more general interface to scheduler
             functions.

       REFERENCES
             exec(2), nice(1), priocntl(2)

       NOTICES
          Considerations for Threads Programming
             The nice system call should not be used to modify the priority
             of threads.  See thr_setprio(3thread).



                           Copyright 1994 Novell, Inc.               Page 1

      nice(2)                                                      nice(2)


         Considerations for Lightweight Processes
            Scheduling context is not a process attribute, a separate
            context is internally maintained for each LWP.  A call to nice
            shall bias only the priority of the calling LWP by the applied
            nice value.

            A process can contain LWPs belonging to different scheduling
            classes.








































                          Copyright 1994 Novell, Inc.               Page 2