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 process in the time-sharing scheduling class to change
         its priority.  The priocntl system call is a more general interface
         to scheduler functions.

         nice adds the value of incr to the nice value of the calling process.
         A process's 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.

         EPERM         nice fails and does not change the nice value if incr
                       is negative or greater than 39 and the effective user
                       ID of the calling process is not super-user.

         EINVAL        nice fails if called by a process in a scheduling class
                       other than time-sharing.

   SEE ALSO
         exec(2), priocntl(2).
         nice(1) in the User's Reference Manual.

   DIAGNOSTICS
         Upon successful completion, nice returns the new nice value minus 20.
         Otherwise, a value of -1 is returned and errno is set to indicate the
         error.

















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