lt; args[_name]
                  &lt;&lt; &quot;; index = &quot; &lt;&lt; args[_index | 42]
                  &lt;&lt; std::endl;
    }
};
</pre>
<!-- @example.prepend('''
#include <boost/parameter.hpp>
#include <iostream>''') -->
<p>Note that the bitwise or (“<tt class="docutils literal">|</tt>”) operator has a special
meaning when applied to keyword objects that are passed to an
<span class="concept">ArgumentPack</span>'s indexing operator: it is used to indicate a
default value.  In this case if the