PTHREAD_ATTR_AFFINITY_NP(3)				   BSD Library Functions Manual 			       PTHREAD_ATTR_AFFINITY_NP(3)

NAME

     pthread_attr_getaffinity_np, pthread_attr_setaffinity_np -- manage CPU affinity in thread attribute objects

LIBRARY

     POSIX Threads Library (libpthread, -lpthread)

SYNOPSIS

     #include <pthread_np.h>

     int
     pthread_attr_getaffinity_np(const pthread_attr_t *pattr, size_t cpusetsize, cpuset_t *cpusetp);

     int
     pthread_attr_setaffinity_np(pthread_attr_t *pattr, size_t cpusetsize, const cpuset_t *cpusetp);

DESCRIPTION

     The pthread_attr_getaffinity_np() and pthread_attr_setaffinity_np() functions allow the manipulation of sets of CPUs available to the speci-
     fied thread attribute object.

     Masks of type cpuset_t are composed using the CPU_SET macros.  The kernel tolerates large sets as long as all CPUs specified in the set
     exist.  Sets smaller than the kernel uses generate an error on calls to pthread_attr_getaffinity_np() even if the result set would fit within
     the user supplied set.  Calls to pthread_attr_setaffinity_np() tolerate small sets with no restrictions.

     The supplied mask should have a size of cpusetsize bytes.	This size is usually provided by calling sizeof(cpuset_t) which is ultimately
     determined by the value of CPU_SETSIZE as defined in <sys/cpuset.h>.

     pthread_attr_getaffinity_np() retrieves the mask from the thread attribute object specified by pattr, and stores it in the space provided by
     cpusetp.

     pthread_attr_setaffinity_np() sets the mask for the thread attribute object specified by pattr to the value in cpusetp.

RETURN VALUES

     If successful, the pthread_attr_getaffinity_np() and pthread_attr_setaffinity_np() functions will return zero.  Otherwise an error number
     will be returned to indicate the error.

ERRORS

     The pthread_attr_getaffinity_np() functions will fail if:

     [EINVAL]		The pattr or the attribute specified by it is NULL.

     [ERANGE]		The cpusetsize is too small.

     The pthread_attr_setaffinity_np() function will fail if:

     [EINVAL]		The pattr or the attribute specified by it is NULL.

     [EINVAL]		The cpusetp specified a CPU that was outside the set supported by the kernel.

     [ERANGE]		The cpusetsize is too small.

     [ENOMEM]		Insufficient memory exists to store the cpuset mask.

SEE ALSO

     cpuset(1), cpuset(2), cpuset_getid(2), cpuset_setid(2), pthread_get_affinity_np(3), pthread_set_affinity_np(3)

STANDARDS

     The pthread_attr_getaffinity_np and pthread_attr_setaffinity_np functions are non-standard FreeBSD extensions and may be not available on
     other operating systems.

HISTORY

     The pthread_attr_getaffinity_np and pthread_attr_setaffinity_np functions first appeared in FreeBSD 7.2.

AUTHORS

     The pthread_attr_getaffinity_np and pthread_attr_setaffinity_np functions were written by David Xu <davidxu@FreeBSD.org>, and this manpage
     was written by Xin LI <delphij@FreeBSD.org>.

BSD
								  January 8, 2010							       BSD