nice(3) [netbsd man page]

NICE(3) 						   BSD Library Functions Manual 						   NICE(3)

NAME

     nice -- set program scheduling priority

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <unistd.h>

     int
     nice(int incr);

DESCRIPTION

     This interface is obsoleted by setpriority(2).

     The nice() function obtains the scheduling priority of the process from the system and sets it to the priority value specified in incr.  The
     priority is a value in the range -20 to 20.  The default priority is 0; lower priorities cause more favorable scheduling.	Only a process
     with appropriate privileges may lower priorities.

     Children inherit the priority of their parent processes via fork(2).

RETURN VALUES

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

ERRORS

     The nice() function will fail if:

     [EPERM]		The incr argument is negative and the caller does not have appropriate privileges.

SEE ALSO

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

STANDARDS

     The nice() function conforms to X/Open Portability Guide Issue 4, Version 2 (``XPG4.2'').

HISTORY

     A nice() syscall appeared in Version 6 AT&T UNIX.

BSD
								  April 30, 2011							       BSD

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)