Boost asio tcp server example, C++11

server.cpp

#include <iostream>
#include <memory>
#include <boost/asio.hpp>
#include <boost/bind.hpp>

//thanks kalven for tips/debugging

using boost::asio::ip::tcp;

class Session : public std::enable_shared_from_this<Session>
{
public:
  Session(boost::asio::io_service& ios)
    : socket(ios) {}
  
  tcp::socket& get_socket()
  {
    return socket;
  }

  void start()
  {
    socket.async_read_some(
        boost::asio::buffer(data, max_length),
        boost::bind(&Session::handle_read, this,
                    shared_from_this(),
                    boost::asio::placeholders::error,
                    boost::asio::placeholders::bytes_transferred));
  }

  void handle_read(std::shared_ptr<Session>& s,
                   const boost::system::error_code& err,
                   size_t bytes_transferred)
  {
    if (!err) {
      std::cout << "recv: " + test << std::endl;
      socket.async_read_some(
          boost::asio::buffer(data, max_length),
          boost::bind(&Session::handle_read, this,
                      shared_from_this(),
                      boost::asio::placeholders::error,
                      boost::asio::placeholders::bytes_transferred));
    } else {
      std::cerr << "err (recv): " << err.message() << std::endl;
    }
  }

private:
  tcp::socket socket;
  enum { max_length = 1024 };
  char data[max_length];
};

class Server {
public:
  Server(boost::asio::io_service& ios,
         short port) : ios(ios), acceptor(ios, tcp::endpoint(tcp::v4(), port))
  {
    std::shared_ptr<Session> session = std::make_shared<Session>(ios);
    acceptor.async_accept(session->get_socket(),
                          boost::bind(&Server::handle_accept, this,
                                      session,
                                      boost::asio::placeholders::error));
  }

  void handle_accept(std::shared_ptr<Session> session,
                     const boost::system::error_code& err)
  {
    if (!err) {
      session->start();
      session = std::make_shared<Session>(ios);
      acceptor.async_accept(session->get_socket(),
                            boost::bind(&Server::handle_accept, this, session,
                                        boost::asio::placeholders::error));
    }
    else {
      std::cerr << "err: " + err.message() << std::endl;
      session.reset();
    }
  }
private:
  boost::asio::io_service& ios;
  tcp::acceptor acceptor;
};

int main(int argc, char *argv[])
{
  try {
    boost::asio::io_service ios;
    Server s(ios, 8080);
    ios.run();
  } catch(std::exception& e) {
    std::cerr << e.what() << std::endl;
  }
  return 0;
}

36 std::cout << "recv: " + test << std::endl;

What is "test"?

good question
only 1 reference, fails to compile, compiles broken when removed

Well, this was written 4 years ago so I'm not really sure what I was doing with test here, but you can just remove it. Compiles with warnings when removed: https://wandbox.org/permlink/yNAo9pw7HQQCeMDO

I haven't done cpp in a long time so I don't recommend using this without fixing all the warnings.