nice(3) [ultrix man page]

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)

nice(2) 							   System Calls 							   nice(2)

NAME

       nice - change priority of a process

SYNOPSIS

       #include <unistd.h>

       int nice(int incr);

DESCRIPTION

       The nice() function allows a process to change its priority.  The invoking  process must be in a scheduling class that supports the nice().

       The  nice()  function 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 greater positive value results in lower CPU priority.

       A maximum nice value of (2 * NZERO) -1 and a minimum nice value of 0 are imposed by the system. NZERO  is  defined  in  <limits.h>  with  a
       default	value of 20. Requests for values above or below these limits result in the nice value being set to the corresponding limit. A nice
       value of 40 is treated as 39.

       Calling the nice() function has no effect on the priority of processes or threads with policy SCHED_FIFO or SCHED_RR.

       Only a process with the {PRIV_PROC_PRIOCNTL} privilege can lower the nice value.

RETURN VALUES

       Upon successful completion, nice() returns the new nice value minus NZERO. Otherwise, -1 is returned,  the  process's  nice  value  is  not
       changed, and errno is set to indicate the error.

ERRORS

       The nice() function will fail if:

       EINVAL	The nice() function is called by a process in a scheduling class other than time-sharing or fixed-priority.

       EPERM	The  incr  argument  is negative or greater than 40 and the {PRIV_PROC_PRIOCNTL} privilege is not asserted in the effective set of
		the calling process.

USAGE

       The priocntl(2) function is a more general interface to scheduler functions.

       Since -1 is a permissible return value in a successful situation, an application wishing to check for error situations should set errno	to
       0, then call nice(), and if it returns -1, check to see if errno is non-zero.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       nice(1), exec(2), priocntl(2), getpriority(3C), attributes(5), privileges(5), standards(5)

SunOS 5.10							    1 Apr 2004								   nice(2)