affinity attribute in thread attributes object
#define _GNU_SOURCE /* See feature_test_macros(7) */
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() 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
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
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 nonstandard GNU extensions; hence the suffix "_np"
(nonportable) in the names.
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2010-09-10 PTHREAD_ATTR_SETAFFINITY_NP(3)
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