nice(2)                   SYSTEM CALLS                    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  prior-
     ity.

     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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