NAME

std::thread::hardware_concurrency - std::thread::hardware_concurrency

Synopsis

static unsigned int hardware_concurrency() noexcept; (since C++11)

Returns the number of concurrent threads supported by the implementation. The value
should be considered only a hint.

Parameters

(none)

Return value

Number of concurrent threads supported. If the value is not well defined or not
computable, returns 0.

Example

// Run this code

#include <iostream>
#include <thread>

int main() {
unsigned int n = std::thread::hardware_concurrency();
std::cout << n << " concurrent threads are supported.\n";
}

Possible output:

4 concurrent threads are supported.

See also

hardware_destructive_interference_size min offset to avoid false sharing
hardware_constructive_interference_size max offset to promote true sharing
(C++17) (constant)