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POHow to asynchronously read to std::string using Boost::asio?
 

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  1. POHow to asynchronously read to std::string using Boost::asio?
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    <p>I'm learning Boost::asio and all that async stuff. How can I asynchronously read to variable <code>user_</code> of type std::string? <code>Boost::asio::buffer(user_)</code> works only with <code>async_write()</code>, but not with <code>async_read()</code>. It works with vector, so what is the reason for it not to work with string? Is there another way to do that besides declaring <code>char user_[max_len]</code> and using <code>Boost::asio::buffer(user_, max_len)</code>?</p> <p>Also, what's the point of inheriting from <code>boost::enable_shared_from_this&lt;Connection&gt;</code> and using <code>shared_from_this()</code> instead of <code>this</code> in <code>async_read()</code> and <code>async_write()</code>? I've seen that a lot in the examples.</p> <p>Here is a part of my code:</p> <pre><code>class Connection { public: Connection(tcp::acceptor &amp;acceptor) : acceptor_(acceptor), socket_(acceptor.get_io_service(), tcp::v4()) { } void start() { acceptor_.get_io_service().post( boost::bind(&amp;Connection::start_accept, this)); } private: void start_accept() { acceptor_.async_accept(socket_, boost::bind(&amp;Connection::handle_accept, this, placeholders::error)); } void handle_accept(const boost::system::error_code&amp; err) { if (err) { disconnect(); } else { async_read(socket_, boost::asio::buffer(user_), boost::bind(&amp;Connection::handle_user_read, this, placeholders::error, placeholders::bytes_transferred)); } } void handle_user_read(const boost::system::error_code&amp; err, std::size_t bytes_transferred) { if (err) { disconnect(); } else { ... } } ... void disconnect() { socket_.shutdown(tcp::socket::shutdown_both); socket_.close(); socket_.open(tcp::v4()); start_accept(); } tcp::acceptor &amp;acceptor_; tcp::socket socket_; std::string user_; std::string pass_; ... }; </code></pre>
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