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) */
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
These functions are provided by glibc since version 2.3.4.
For an explanation of the terms used in this section, see attributes(7).
- (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.)
- (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
- (pthread_attr_setaffinity_np()) Could not allocate memory.
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).
This page is part of release 5.01 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/.
|pthread_attr_setaffinity_np (), pthread_attr_getaffinity_np ()