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34 .Dt PTHREAD_SETAFFINITY_NP 2
37 .Nm pthread_setaffinity_np ,
38 .Nm pthread_getaffinity_np
39 .Nd set and get the thread's CPU affinity mask
46 .Fn pthread_setaffinity_np "pthread_t tid" "size_t cpusetsize" "const cpu_set_t *mask"
48 .Fn pthread_getaffinity_np "pthread_t tid" "size_t cpusetsize" "cpu_set_t *mask"
51 .Fn pthread_setaffinity_np
52 sets the CPU affinity mask of the thread identified by
54 to the value specified by the
58 is the length (in bytes) of the data pointed to by
60 Normally this argument would be specified as sizeof(cpu_set_t).
61 If the thread specified by the
63 is the current thread,
64 it will be migrated immediately,
65 if necessary, otherwise it will be migrated by the scheduler later.
72 inherits the calling thread's CPU affinity mask.
73 Same applies to the threads created by
75 and the threads created by
76 .Xr pthread_create 3 .
78 .Fn pthread_getaffinity_np
79 writes the affinity mask of the thread
82 to the cpu_set_t structure pointed to by
85 The cpu_set_t data structure represents a set of CPUs.
87 .Xr sched_setaffinity 2
91 these functions will return zero.
92 Otherwise an error number will be returned to indicate the error.
95 .Fn pthread_setaffinity_np
97 .Fn pthread_getaffinity_np
103 parameter is outside the process's allocated address space.
107 parameter is invalid.
109 The thread identified by the
115 does not contain a valid CPU.
120 .Xr lwp_getaffinity 2 ,
121 .Xr lwp_setaffinity 2 ,
123 .Xr sched_getaffinity 2 ,
124 .Xr sched_setaffinity 2 ,
129 .Fn pthread_setaffinity_np
131 .Fn pthread_getaffinity_np
132 functions first appeared in