pthread_attr_setaffinity_np, pthread_attr_getaffinity_np - set/get
CPU affinity attribute in thread attributes object
SYNOPSIS
#define _GNU_SOURCE#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(pthread_attr_t attr, size_t cpusetsize, cpu_set_t *cpuset);
Compile and link with -pthread.
DESCRIPTION
The
pthread_attr_setaffinity_np()
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()
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 non-zero error number.
ERRORS
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.
VERSIONS
These functions are provided by glibc since version 2.3.4.
CONFORMING TO
These functions are non-standard GNU extensions;
hence the suffix "_np" (non-portable) 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).
This page is part of release 3.14 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.
