title: const shared_ptr to shared_ptr
body: <p>How can one convert a shared_ptr that points to a const object to a shared_ptr that points to a non-const object.
  I am trying to do the following :</p>
  
  <pre><code>boost::shared_ptr&lt;const A&gt; Ckk(new A(4));
  
  boost::shared_ptr&lt;A&gt; kk=const_cast&lt; boost::shared_ptr&lt;A&gt; &gt; Ckk;
  </code></pre>
  
  <p>But it does not work. </p>