t;Derived&gt;(p);
!p; // conversion to bool with negation
</pre>
<p>
      This includes C++ built-in pointers, <code class="computeroutput">std::shared_ptr</code>, <code class="computeroutput">boost::shared_ptr</code>,
      <code class="computeroutput">boost::intrusive_ptr</code>, etc.
    </p>
</div>
<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2001 Beman Dawes<p>
       