ex=12, _name=&quot;sam&quot;<strong>)</strong>
);
</pre>
<!-- @example.prepend('''
namespace parameter = boost::parameter;
using parameter::required;
using parameter::optional;
using boost::is_convertible;
using boost::mpl::_;''') -->
<!-- @example.append('''
int main()
{}''') -->
<!-- @test('run', howmany='all') -->
<p>Note that because of the <a class="reference external" href="http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2002/n1385.htm">forwarding problem</a>, <tt class="docutils literal"><span cla