ultrix man page for nice

nice(3) 						     Library Functions Manual							   nice(3)

Name
       nice - set program priority

Syntax
       int nice(incr)
       int incr;

Description
       The scheduling priority of the process is augmented by incr.  Positive priorities get less service than normal.	Priority 10 is recommended
       to users who wish to execute long-running programs without flack from the administration.

       Negative increments are ignored except on behalf of the super-user.  The priority is limited to the range -20 (most urgent) to 20 (least).

       The priority of a process is passed to a child process by For a privileged process to return to normal  priority  from  an  unknown  state,
       should  be  called successively with arguments -40 (goes to priority -20 because of truncation), 20 (to get to 0), then 0 (to maintain com-
       patibility with previous versions of this call).

Environment
       In any mode, nice returns -1 and sets on an error.  On success, the return value depends on the mode in which your  program  was  compiled.
       In  POSIX  or  System V mode, it is the new priority; otherwise, it is zero.  Note that, in POSIX and System V mode, -1 can indicate either
       success or failure; must be used to determine which.

See Also
       nice(1), fork(2), setpriority(2), renice(8)

																	   nice(3)