nice(2)                          UNIX System V                          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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