std::thread::hardware_concurrency (3) - Linux Man Pages

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


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


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.



Return value

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


// 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