h copy
                  will not take ownership of the shared data. This works well for
                  <a href="http://boost-spirit.com" target="_top">Spirit</a>, since no dynamic
                  allocation of iterators is done. All copies are made on the stack,
                  so the original iterator has the longest lifespan.
                </p>
              </td>
</tr>
<tr>
<td>
                <p>
                  <span class="bold"><strong>CheckingPolicy</strong></span> classes
             