title: How to interpret a "const unique_ptr"
body: <pre><code>const unique_ptr&lt;int&gt; upi{new int{4}};
  cout &lt;&lt; ++*upi &lt;&lt; '\n';
  </code></pre>
  
  <p>Seems <code>upi</code> is a <code>const smart pointer</code>. The <code>int</code> it points to can still be modified. What if I want to declare the <code>int</code> as <code>const</code>?</p>
  
  <pre><code>const unqiue_ptr&lt;int&gt; const upi{new int{4}};    //Error: duplicate const
  </code></pre>