title: Is it possible to get current time at compile time?
body: <p>I'm thinking about using current timestamp as a piece of version. I would like to retrieve that information at compile time. So ideally I would like to do:</p>
  
  <pre><code>constexpr long long currentTimestamp = getCurrentTimestamp();
  </code></pre>
  
  <p>Is that possible with C++14?</p>