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NICE(2)			   Linux Programmer's Manual		       NICE(2)

NAME
       nice - change process priority

SYNOPSIS
       #include	<unistd.h>

       int nice(int inc);

   Feature Test	Macro Requirements for glibc (see feature_test_macros(7)):

       nice(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE

DESCRIPTION
       nice()  adds  inc to the	nice value for the calling process.  (A	higher
       nice value means	a low priority.)  Only the  superuser  may  specify  a
       negative	increment, or priority increase.  The range for	nice values is
       described in getpriority(2).

RETURN VALUE
       On success, the new nice	value is returned (but see NOTES  below).   On
       error, -1 is returned, and errno	is set appropriately.

ERRORS
       EPERM  The  calling  process attempted to increase its priority by sup-
	      plying a negative	inc but	has  insufficient  privileges.	 Under
	      Linux,  the  CAP_SYS_NICE	 capability is required.  (But see the
	      discussion of the	RLIMIT_NICE resource limit in setrlimit(2).)

CONFORMING TO
       SVr4, 4.3BSD, POSIX.1-2001.  However, the Linux	and  (g)libc  (earlier
       than  glibc  2.2.4) return value	is nonstandard,	see below.  SVr4 docu-
       ments an	additional EINVAL error	code.

NOTES
       SUSv2 and POSIX.1-2001 specify that nice() should return	the  new  nice
       value.  However,	the Linux syscall and the nice() library function pro-
       vided in	older versions of (g)libc (earlier than	glibc 2.2.4) return  0
       on success.  The	new nice value can be found using getpriority(2).

       Since  glibc  2.2.4,  nice()  is	implemented as a library function that
       calls getpriority(2) to obtain the new nice value to be returned	to the
       caller.	 With  this implementation, a successful call can legitimately
       return -1.  To reliably detect an error,	set  errno  to	0  before  the
       call, and check its value when nice() returns -1.

SEE ALSO
       nice(1),	 renice(1), fork(2), getpriority(2), setpriority(2), capabili-
       ties(7),	sched(7)

COLOPHON
       This page is part of release 3.74 of the	Linux  man-pages  project.   A
       description  of	the project, information about reporting bugs, and the
       latest	 version    of	  this	  page,	   can	   be	  found	    at
       http://www.kernel.org/doc/man-pages/.

Linux				  2014-04-28			       NICE(2)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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