https://svn.boost.org/trac10/ticket/8714 <p> (See also <a class="ext-link" href="http://stackoverflow.com/questions/17211263"><span class="icon">​</span>http://stackoverflow.com/questions/17211263</a>) </p> <p> The requirement that handlers be copy constructible doesn't allow for the following idiom: </p> <pre class="wiki">void connection::send_response() { // block until previous response is sent std::unique_lock&lt;std::mutex&gt; locker(response_mutex_); // prepare response response_ = "foo"; // send response back to caller. move the unique_lock into the binder // to keep the mutex locked until asio is done sending. asio::async_write(stream_, asio::const_buffers_1(response_.data(), response_.size()), std::bind(&amp;connection::response_sent, shared_from_this(), _1, _2, std::move(locker)) ); } void connection::response_sent(const boost::system::error_code&amp; err, std::size_t len) { if (err) handle_error(err); // the mutex is unlocked when the binder is destroyed } </pre><p> Please remove this restriction, there is no reason for it when using C++11. </p> en-us /htdocs/site/boost.png https://svn.boost.org/trac10/ticket/8714 Trac 1.4.3 cristi.cobzarenco@… Thu, 14 Aug 2014 12:19:13 GMT