std::thread::hardware_concurrency

< cpp‎ | thread‎ | thread

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

#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

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