title: How to get GMT time in milliseconds using boost Date_Time?
body: <p>Is there a simple way to get from <code>boost</code> <code>Date_Time</code> library a current <code>GMT</code> time in milliseconds?</p>
  
  <p>Here is one example which uses <code>time_of_day</code>, I don't want <code>time_of_day</code> but <strong>total time in GMT</strong> as <code>long long int</code>:</p>
  
  <pre><code>boost::posix_time::ptime time =
            boost::posix_time::microsec_clock::universal_time();
  boost::posix_time::time_duration duration( time.time_of_day() );  // ???
  long long int timeInMilliseconds = duration.total_milliseconds();
  </code></pre>