nice(3ucb) [opensolaris 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

       cc(1B), 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 5.11							    30 Oct 2007 							nice(3UCB)

NICE(P) 						     POSIX Programmer's Manual							   NICE(P)

NAME

       nice - change the nice value of a process

SYNOPSIS

       #include <unistd.h>

       int nice(int incr);

DESCRIPTION

       The  nice()  function  shall add the value of incr to the nice value of the calling process. A process' nice value is a non-negative number
       for which a more positive value shall result in less favorable scheduling.

       A maximum nice value of 2*{NZERO}-1 and a minimum nice value of 0 shall be imposed by the system. Requests for values above or below  these
       limits  shall  result in the nice value being set to the corresponding limit. Only a process with appropriate privileges can lower the nice
       value.

       Calling the nice() function has no effect on the priority of processes or threads with policy SCHED_FIFO or SCHED_RR. The  effect  on  pro-
       cesses or threads with other scheduling policies is implementation-defined.

       The  nice  value set with nice() shall be applied to the process.  If the process is multi-threaded, the nice value shall affect all system
       scope threads in the process.

       As -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 whether errno is non-zero.

RETURN VALUE

       Upon successful completion, nice() shall return the new nice value -{NZERO}. Otherwise, -1 shall be returned, the process' nice value shall
       not be changed, and errno shall be set to indicate the error.

ERRORS

       The nice() function shall fail if:

       EPERM  The incr argument is negative and the calling process does not have appropriate privileges.

       The following sections are informative.

EXAMPLES

   Changing the Nice Value
       The following example adds the value of the incr argument, -20, to the nice value of the calling process.

	      #include <unistd.h>
	      ...
	      int incr = -20;
	      int ret;

	      ret = nice(incr);

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       getpriority() , setpriority() , the Base Definitions volume of IEEE Std 1003.1-2001, <limits.h>, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and  the  original  IEEE
       and  The  Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
       online at http://www.opengroup.org/unix/online.html .

IEEE
/The Open Group						       2003								   NICE(P)