title: how to round up to the next hour given a boost::posix_time::ptime
body: <p>Given</p>
  
  <pre><code>boost::posix_time::ptime aTime( time_from_string("2012-01-01 11:15:00"));
  </code></pre>
  
  <p>My function will return 2012-01-01 12:00:00</p>
  
  <p>or given boundary case:</p>
  
  <pre><code>boost::posix_time::ptime boundaryTime( time_from_string("2012-01-01 23:45:00"));
  </code></pre>
  
  <p>My function will return</p>
  
  <pre><code>2012-01-02 00:00:00
  </code></pre>