title: Standard Library version of "Wait for Alert/Event" for threading
body: <p>Does C++ have any notion of thread synchronization by Wait+Wake of some kind? Waiting on an event, alert, object, etc? Something like <code>WaitForSingleObject</code>, WaitOnAddress, etc? The only things I can find are <code>std::thread::join</code>, and fence/sync stuff like locks and <code>std::atomic</code>. Is there more to C++'s threading yet? Is there more coming in the future?</p>