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28 .Dt PTHREAD_ATTR_AFFINITY_NP 3
31 .Nm pthread_attr_getaffinity_np ,
32 .Nm pthread_attr_setaffinity_np
33 .Nd manage CPU affinity in thread attribute objects
39 .Fn pthread_attr_getaffinity_np "const pthread_attr_t *pattr" "size_t cpusetsize" "cpuset_t *cpusetp"
41 .Fn pthread_attr_setaffinity_np "pthread_attr_t *pattr" "size_t cpusetsize" "const cpuset_t *cpusetp"
44 .Fn pthread_attr_getaffinity_np
46 .Fn pthread_attr_setaffinity_np
47 functions allow the manipulation of sets of CPUs available to the specified thread attribute object.
51 are composed using the
54 The kernel tolerates large sets as long as all CPUs specified
56 Sets smaller than the kernel uses generate an error on calls to
57 .Fn pthread_attr_getaffinity_np
58 even if the result set would fit within the user supplied set.
60 .Fn pthread_attr_setaffinity_np
61 tolerate small sets with no restrictions.
63 The supplied mask should have a size of
66 This size is usually provided by calling
68 which is ultimately determined by the value of
73 .Fn pthread_attr_getaffinity_np
75 mask from the thread attribute object specified by
77 and stores it in the space provided by
80 .Fn pthread_attr_setaffinity_np
81 sets the mask for the thread attribute object specified by
87 .Fn pthread_attr_getaffinity_np
89 .Fn pthread_attr_setaffinity_np
90 functions will return zero.
91 Otherwise an error number will be returned
92 to indicate the error.
95 .Fn pthread_attr_getaffinity_np
96 functions will fail if:
101 or the attribute specified by it is
110 .Fn pthread_attr_setaffinity_np
111 function will fail if:
116 or the attribute specified by it is
121 specified a CPU that was outside the set supported by the kernel.
127 Insufficient memory exists to store the cpuset mask.
134 .Xr pthread_getaffinity_np 3 ,
135 .Xr pthread_setaffinity_np 3
138 .Nm pthread_attr_getaffinity_np
140 .Nm pthread_attr_setaffinity_np
141 functions are non-standard
143 extensions and may be not available on other operating systems.
146 .Nm pthread_attr_getaffinity_np
148 .Nm pthread_attr_setaffinity_np
149 functions first appeared in
154 .Nm pthread_attr_getaffinity_np
156 .Nm pthread_attr_setaffinity_np
157 functions were written by
158 .An David Xu Aq Mt davidxu@FreeBSD.org ,
159 and this manpage was written by
160 .An Xin LI Aq Mt delphij@FreeBSD.org .