nice(2)								       nice(2)

NAME    [Toc]    [Back]

     nice - change priority of a time-sharing process

SYNOPSIS    [Toc]    [Back]

     #include <unistd.h>

     int nice(int incr);

DESCRIPTION    [Toc]    [Back]

     nice allows a process in the time-sharing scheduling class	to change its
     priority.	The sched_setscheduler and schedctl system calls are more
     general interfaces	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 40 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    [Toc]    [Back]

     exec(2), setpriority(2), sched_setscheduler(2).  schedctl(2).
     csh(1), sh(1), nice(1).

DIAGNOSTICS    [Toc]    [Back]

     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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