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
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.
The pthread_attr_setaffinity_np() sets the CPU affinity mask attribute
of the thread attributes object referred to by attr to the value speci‐
fied 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
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 non-zero
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
ENOMEM (pthread_attr_setaffinity_np()) Could not allocate memory.
These functions are provided by glibc since version 2.3.4.
These functions are non-standard GNU extensions; hence the suffix "_np"
(non-portable) 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).
SEE ALSOsched_setaffinity(2), pthread_attr_init(3), pthread_setaffinity_np(3),
This page is part of release 3.22 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/.
Linux 2009-02-01 PTHREAD_ATTR_SETAFFINITY_NP(3)