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<title>async_connect (3 of 6 overloads)</title>
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<div class="titlepage"><div><div><h4 class="title">
<a name="boost_asio.reference.async_connect.overload3"></a><a class="link" href="overload3.html" title="async_connect (3 of 6 overloads)">async_connect
        (3 of 6 overloads)</a>
</h4></div></div></div>
<p>
          Asynchronously establishes a socket connection by trying each endpoint
          in a sequence.
        </p>
<pre class="programlisting">template&lt;
    typename <a class="link" href="../Protocol.html" title="Protocol requirements">Protocol</a>,
    typename Iterator,
    typename <a class="link" href="../IteratorConnectHandler.html" title="Iterator connect handler requirements">IteratorConnectHandler</a>&gt;
<a class="link" href="../asynchronous_operations/automatic_deduction_of_initiating_function_return_type.html" title="Automatic deduction of initiating function return type"><span class="emphasis"><em>DEDUCED</em></span></a> async_connect(
    basic_socket&lt; Protocol &gt; &amp; s,
    Iterator begin,
    Iterator end,
    IteratorConnectHandler &amp;&amp; handler);
</pre>
<p>
          This function attempts to connect a socket to one of a sequence of endpoints.
          It does this by repeated calls to the socket's <code class="computeroutput">async_connect</code>
          member function, once for each endpoint in the sequence, until a connection
          is successfully established.
        </p>
<h6>
<a name="boost_asio.reference.async_connect.overload3.h0"></a>
          <span class="phrase"><a name="boost_asio.reference.async_connect.overload3.parameters"></a></span><a class="link" href="overload3.html#boost_asio.reference.async_connect.overload3.parameters">Parameters</a>
        </h6>
<div class="variablelist">
<p class="title"><b></b></p>
<dl class="variablelist">
<dt><span class="term">s</span></dt>
<dd><p>
                The socket to be connected. If the socket is already open, it will
                be closed.
              </p></dd>
<dt><span class="term">begin</span></dt>
<dd><p>
                An iterator pointing to the start of a sequence of endpoints.
              </p></dd>
<dt><span class="term">end</span></dt>
<dd><p>
                An iterator pointing to the end of a sequence of endpoints.
              </p></dd>
<dt><span class="term">handler</span></dt>
<dd>
<p>
                The handler to be called when the connect operation completes. Copies
                will be made of the handler as required. The function signature of
                the handler must be:
</p>
<pre class="programlisting">void handler(
  // Result of operation. if the sequence is empty, set to
  // boost::asio::error::not_found. Otherwise, contains the
  // error from the last connection attempt.
  const boost::system::error_code&amp; error,

  // On success, an iterator denoting the successfully
  // connected endpoint. Otherwise, the end iterator.
  Iterator iterator
);
</pre>
<p>
                Regardless of whether the asynchronous operation completes immediately
                or not, the handler will not be invoked from within this function.
                Invocation of the handler will be performed in a manner equivalent
                to using <code class="computeroutput">boost::asio::io_context::post()</code>.
              </p>
</dd>
</dl>
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<h6>
<a name="boost_asio.reference.async_connect.overload3.h1"></a>
          <span class="phrase"><a name="boost_asio.reference.async_connect.overload3.example"></a></span><a class="link" href="overload3.html#boost_asio.reference.async_connect.overload3.example">Example</a>
        </h6>
<pre class="programlisting">std::vector&lt;tcp::endpoint&gt; endpoints = ...;
tcp::socket s(io_context);
boost::asio::async_connect(s,
    endpoints.begin(), endpoints.end(),
    connect_handler);

// ...

void connect_handler(
    const boost::system::error_code&amp; ec,
    std::vector&lt;tcp::endpoint&gt;::iterator i)
{
  // ...
}
</pre>
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<td align="right"><div class="copyright-footer">Copyright &#169; 2003-2017 Christopher M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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