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$FreeBSD: releng/10.2/share/man/man3/pthread_attr_affinity_np.3 249716 2013-04-21 06:46:41Z joel $
.Dd January 8, 2010 .Dt PTHREAD_ATTR_AFFINITY_NP 3 .Os .Sh NAME .Nm pthread_attr_getaffinity_np , .Nm pthread_attr_setaffinity_np .Nd manage CPU affinity in thread attribute objects .Sh LIBRARY .Lb libpthread .Sh SYNOPSIS n pthread_np.h .Ft int .Fn pthread_attr_getaffinity_np "const pthread_attr_t *pattr" "size_t cpusetsize" "cpuset_t *cpusetp" .Ft int .Fn pthread_attr_setaffinity_np "pthread_attr_t *pattr" "size_t cpusetsize" "const cpuset_t *cpusetp" .Sh DESCRIPTION The .Fn pthread_attr_getaffinity_np and .Fn pthread_attr_setaffinity_np functions allow the manipulation of sets of CPUs available to the specified thread attribute object.
p Masks of type .Ft cpuset_t are composed using the .Dv 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 .Fn pthread_attr_getaffinity_np even if the result set would fit within the user supplied set. Calls to .Fn pthread_attr_setaffinity_np tolerate small sets with no restrictions.
p The supplied mask should have a size of .Fa cpusetsize bytes. This size is usually provided by calling .Li sizeof(cpuset_t) which is ultimately determined by the value of .Dv CPU_SETSIZE as defined in n sys/cpuset.h .
p .Fn pthread_attr_getaffinity_np retrieves the mask from the thread attribute object specified by .Fa pattr , and stores it in the space provided by .Fa cpusetp .
p .Fn pthread_attr_setaffinity_np sets the mask for the thread attribute object specified by .Fa pattr to the value in .Fa cpusetp . .Sh RETURN VALUES If successful, the .Fn pthread_attr_getaffinity_np and .Fn pthread_attr_setaffinity_np functions will return zero. Otherwise an error number will be returned to indicate the error. .Sh ERRORS The .Fn pthread_attr_getaffinity_np functions will fail if: l -tag -width Er t Bq Er EINVAL The .Fa pattr or the attribute specified by it is .Dv NULL . t Bq Er ERANGE The .Fa cpusetsize is too small. .El
p The .Fn pthread_attr_setaffinity_np function will fail if: l -tag -width Er t Bq Er EINVAL The .Fa pattr or the attribute specified by it is .Dv NULL . t Bq Er EINVAL The .Fa cpusetp specified a CPU that was outside the set supported by the kernel. t Bq Er ERANGE The .Fa cpusetsize is too small. t Bq Er ENOMEM Insufficient memory exists to store the cpuset mask. .El .Sh SEE ALSO .Xr cpuset 1 , .Xr cpuset 2 , .Xr cpuset_getid 2 , .Xr cpuset_setid 2 , .Xr pthread_get_affinity_np 3 , .Xr pthread_set_affinity_np 3 .Sh STANDARDS The .Nm pthread_attr_getaffinity_np and .Nm pthread_attr_setaffinity_np functions are non-standard .Fx extensions and may be not available on other operating systems. .Sh HISTORY The .Nm pthread_attr_getaffinity_np and .Nm pthread_attr_setaffinity_np functions first appeared in .Fx 7.2 . .Sh AUTHORS .An -nosplit The .Nm pthread_attr_getaffinity_np and .Nm pthread_attr_setaffinity_np functions were written by .An David Xu Aq davidxu@FreeBSD.org , and this manpage was written by .An Xin LI Aq delphij@FreeBSD.org .