The Perform template std::async runs the purpose f asynchronously (potentially in the separate thread which might be a Section of a thread pool) and returns a std::future that will finally hold the result of that purpose call. 1) Behaves like (two) is named with plan being std::launch::async std::future referring to https://alphawireless.com/future-proofing-american-utilities-why-900-mhz-is-critical-for-utility-communications/