e non-const object while output archives require that any
serialized object (with the exception of a wrapper) be const. 

This header file <a href="../../../boost/serialization/wrapper.hpp">wrapper.hpp</a>
includes the following code:

<pre><code>
namespace boost { 
namespace serialization {
template&lt;class T&gt;
struct is_wrapper
 : public mpl::false_
{};
} // namespace serialization
} // namespace boost
</code></pre>

For any class <code style="white-space: normal">T</code>, The default definition 
of <