title: Cannot use movable objects with Boost.Asio
body: <p>Reading <a href="http://www.boost.org/doc/libs/1_54_0/doc/html/boost_asio/overview/cpp2011/move_objects.html">this</a>, I got the impression that this code should work:</p>
  
  <pre><code>class Connection : public std::enable_shared_from_this&lt;Connection&gt;
  {
  public:
      Connection(tcp::socket&amp;&amp; socket) : socket_(std::move(socket)) {}
  private:
      tcp::socket socket_;
  };
  </code></pre>
  
  <p>But the compiler issues this error in the constructor:</p>
  
  <pre><code>Call to implicitly-deleted copy constructor of 'tcp::socket' (aka'basic_stream_socket&lt;boost::asio::ip::tcp&gt;')
  </code></pre>
  
  <p>I have also defined <code>BOOST_ASIO_HAS_MOVE</code> . I use Xcode 4.6.3 and in the compiler settings I have this defined:</p>
  
  <pre><code>C++ Language dialect: GNU++11[-std=gnu++11]
  C++ Standard Library: libc++(LLVM C++ standard library with C++11 support)
  </code></pre>