title: c++, std::atomic, what is std::memory_order and how to use them?
body: <p>Can anyone explain what is <code>std::memory_order</code> in plain English, and how to use them with <code>std::atomic&lt;&gt;</code>?</p>
  
  <p>I found the reference and few examples here, but don't understand at all.
  <a href="http://en.cppreference.com/w/cpp/atomic/memory_order" rel="noreferrer">http://en.cppreference.com/w/cpp/atomic/memory_order</a></p>