AFFINITY(3)             NetBSD Library Functions Manual            AFFINITY(3)

NAME
     pthread_setaffinity_np, pthread_getaffinity_np -- affinity of threads

LIBRARY
     POSIX Threads Library (libpthread, -lpthread)

SYNOPSIS
     #include <pthread.h>
     #include <sched.h>

     int
     pthread_setaffinity_np(pthread_t thread, size_t size, cpuset_t *set);

     int
     pthread_getaffinity_np(pthread_t thread, size_t size, cpuset_t *set);

DESCRIPTION
     Thread affinity allows to run the thread on specified CPU or CPUs only.

     pthread_setaffinity_np() function sets the affinity mask set for thread.
     At least one valid CPU must be set in the mask.

     The pthread_getaffinity_np() function gets the affinity mask of thread
     into set.

     Note that set must be created and initialized using the cpuset(3) func-
     tions.

RETURN VALUES
     The pthread_setaffinity_np() and pthread_getaffinity_np() functions
     return 0 on success.  Otherwise, an error number is returned to indicate
     the error.

EXAMPLES
     An example of code fragment, which sets the affinity for the current
     thread to the CPU whose ID is 0:

             cpuset_t *cset;
             pthread_t pth;
             cpuid_t ci;

             cset = cpuset_create();
             if (cset == NULL) {
                     err(EXIT_FAILURE, "cpuset_create");
             }
             ci = 0;
             cpuset_set(ci, cset);

             pth = pthread_self();
             error = pthread_setaffinity_np(pth, cpuset_size(cset), cset);
             if (error) {
                     ...
             }
             cpuset_destroy(cset);

ERRORS
     The pthread_setaffinity_np() and pthread_getaffinity_np() functions fail
     if:

     [EINVAL]           The specified set was invalid.

     [EPERM]            The calling process lacks the appropriate privileges
                        to perform the operation.

     [ESRCH]            No thread could be found corresponding to the one
                        specified by thread.

NOTES
     There is an alternative processor sets interface, see pset(3).  However,
     thread affinity and processor sets are mutually exclusive, hence mixing
     of these interfaces is prohibited.

SEE ALSO
     cpuset(3), pset(3), pthread_getschedparam(3), pthread_setschedparam(3),
     sched(3), schedctl(8)

NetBSD 5.0_RC4                 October 18, 2008                 NetBSD 5.0_RC4

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