The Purpose template std::async operates the purpose f asynchronously (possibly inside of a independent thread which could be considered a part of a thread pool) and returns a std::future that will finally keep the result of that purpose call. 1) Behaves just as if (two) is named with coverage remaining https://alphawireless.com/future-proofing-american-utilities-why-900-mhz-is-critical-for-utility-communications/