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PTHREAD_ATTR_SETAFFINITY_NP(3)Programmer'sPManual_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 5.10 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)
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)
Copyright and license for this manual page
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