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man:pthread_attr_getaffinity_np

PTHREAD_ATTR_SETAFFINITY_NPLinux Programmer's MaPTHREAD_ATTR_SETAFFINITY_NP(3)

NAME

     pthread_attr_setaffinity_np,  pthread_attr_getaffinity_np - set/get CPU
     affinity attribute in thread attributes object

SYNOPSIS

     #define _GNU_SOURCE             /* See feature_test_macros(7) */
     #include <pthread.h>
     int pthread_attr_setaffinity_np(pthread_attr_t *attr,
                        size_t cpusetsize, const cpu_set_t *cpuset);
     int pthread_attr_getaffinity_np(const pthread_attr_t *attr,
                        size_t cpusetsize, cpu_set_t *cpuset);
     Compile and link with -pthread.

DESCRIPTION

     The pthread_attr_setaffinity_np() function sets the CPU  affinity  mask
     attribute  of  the  thread attributes object referred to by attr to the
     value specified in cpuset.  This attribute determines the CPU  affinity
     mask of a thread created using the thread attributes object attr.
     The  pthread_attr_getaffinity_np()  function  returns  the CPU affinity
     mask attribute of the thread attributes object referred to by  attr  in
     the buffer pointed to by cpuset.
     The  argument cpusetsize is the length (in bytes) of the buffer pointed
     to  by  cpuset.   Typically,  this  argument  would  be  specified   as
     sizeof(cpu_set_t).
     For  more details on CPU affinity masks, see sched_setaffinity(2).  For
     a description of a set of macros that can be  used  to  manipulate  and
     inspect CPU sets, see CPU_SET(3).

RETURN VALUE

     On  success,  these functions return 0; on error, they return a nonzero
     error number.

ERRORS

     EINVAL (pthread_attr_setaffinity_np()) cpuset specified a CPU that  was
            outside the set supported by the kernel.  (The kernel configura-
            tion option CONFIG_NR_CPUS defines the range  of  the  set  sup-
            ported by the kernel data type used to represent CPU sets.)
     EINVAL (pthread_attr_getaffinity_np())  A  CPU  in the affinity mask of
            the thread attributes object referred to by  attr  lies  outside
            the  range  specified  by cpusetsize (i.e., cpuset/cpusetsize is
            too small).
     ENOMEM (pthread_attr_setaffinity_np()) Could not allocate memory.

VERSIONS

     These functions are provided by glibc since version 2.3.4.

ATTRIBUTES

     For  an  explanation  of  the  terms  used   in   this   section,   see
     attributes(7).
     allbox;   lbw30   lb   lb   l   l   l.    Interface Attribute Value  T{
     pthread_attr_setaffinity_np(),            pthread_attr_getaffinity_np()
     T}   Thread safety  MT-Safe

CONFORMING TO

     These  functions are nonstandard GNU extensions; hence the suffix "_np"
     (nonportable) in the names.

NOTES

     In glibc 2.3.3 only, versions of these functions were provided that did
     not  have a cpusetsize argument.  Instead the CPU set size given to the
     underlying system calls was always sizeof(cpu_set_t).

SEE ALSO

     sched_setaffinity(2), pthread_attr_init(3),  pthread_setaffinity_np(3),
     cpuset(7), pthreads(7)

COLOPHON

     This  page  is  part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs,  and  the
     latest     version     of     this    page,    can    be    found    at
     https://www.kernel.org/doc/man-pages/.

Linux 2017-09-15 PTHREAD_ATTR_SETAFFINITY_NP(3)

/data/webs/external/dokuwiki/data/pages/man/pthread_attr_getaffinity_np.txt · Last modified: 2019/05/17 09:47 by 127.0.0.1

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