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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | ATTRIBUTES | CONFORMING TO | NOTES | SEE ALSO | COLOPHON |
PTHREAD_ATTR_SETAFFINITY_NP(3)x Programmer's ManualAD_ATTR_SETAFFINITY_NP(3)
pthread_attr_setaffinity_np, pthread_attr_getaffinity_np - set/get
CPU affinity attribute in thread attributes object
#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.
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).
On success, these functions return 0; on error, they return a nonzero
error number.
EINVAL (pthread_attr_setaffinity_np()) cpuset specified a CPU that
was outside the set supported by the kernel. (The kernel
configuration option CONFIG_NR_CPUS defines the range of the
set supported 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.
These functions are provided by glibc since version 2.3.4.
For an explanation of the terms used in this section, see
attributes(7).
┌───────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├───────────────────────────────┼───────────────┼─────────┤
│pthread_attr_setaffinity_np(), │ Thread safety │ MT-Safe │
│pthread_attr_getaffinity_np() │ │ │
└───────────────────────────────┴───────────────┴─────────┘
These functions are nonstandard GNU extensions; hence the suffix
"_np" (nonportable) in the names.
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).
sched_setaffinity(2), pthread_attr_init(3),
pthread_setaffinity_np(3), cpuset(7), pthreads(7)
This page is part of release 4.12 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 2015-07-23 PTHREAD_ATTR_SETAFFINITY_NP(3)
Pages that refer to this page: CPU_SET(3), pthread_attr_init(3), pthread_attr_setscope(3), pthread_getattr_default_np(3), pthread_getattr_np(3), pthread_setaffinity_np(3)