d>
<p>
                  The function object to be used for verifying a certificate. The
                  function signature of the handler must be:
</p>
<pre class="programlisting">bool verify_callback(
  bool preverified, // True if the certificate passed pre-verification.
  verify_context&amp; ctx // The peer certificate and other context.
);
</pre>
<p>
                  The return value of the callback is true if the certificate has
                  passed verification, false otherwise.
              