nice(3ucb) [sunos man page]

nice(3UCB)					     SunOS/BSD Compatibility Library Functions						nice(3UCB)

NAME

       nice - change priority of a process

SYNOPSIS

       /usr/ucb/cc[ flag ... ] file ...
       #include<unistd.h>

       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 undue impact on system performance.

       Negative increments are illegal, except when specified by the privileged user. The priority is limited to the range -20 (most urgent) to 20
       (least). Requests for values above or below these limits result in the scheduling priority being set to the corresponding limit.

       The  priority  of a process is passed to a child process by fork(2).  For a privileged process to return to normal priority from an unknown
       state, nice() should be called successively with arguments -40 (goes to priority -20 because of truncation), 20 (to get to 0), then  0  (to
       maintain compatibility with previous versions of this call).

RETURN VALUES

       Upon successful completion, nice() returns 0. Otherwise, a value of -1 is returned and errno is set to indicate the error.

ERRORS

       The priority is not changed if:

       EPERM	       The value of incr specified was negative, and the effective user ID is not the privileged user.

SEE ALSO

       nice(1), renice(1), fork(2), priocntl(2), getpriority(3C)

NOTES

       Use of these interfaces should be restricted to only applications written on BSD platforms.  Use of these interfaces with any of the system
       libraries or in multi-threaded applications is unsupported.

SunOS 5.10							    12 Feb 1993 							nice(3UCB)

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)