#define MEM_FN(x)       boost::bind(&self_type::x, shared_from_this())
#define MEM_FN1(x,y)    boost::bind(&self_type::x, shared_from_
this(),y)
#define MEM_FN2(x,y,z)  boost::bind(&self_type::x, shared_from_
this(),y,z)

class talk_to_svr : public boost::enable_shared_from_this<talk_to_svr>
                  , boost::noncopyable {

    typedef talk_to_svr self_type;
    talk_to_svr(const std::string & username)

      : sock_(service), started_(true), username_(username), timer_
(service) {}

    void start(ip::tcp::endpoint ep) {
        sock_.async_connect(ep, MEM_FN1(on_connect,_1));

} public:

    typedef boost::system::error_code error_code;
    typedef boost::shared_ptr<talk_to_svr> ptr;

    static ptr start(ip::tcp::endpoint ep, const std::string &
username) {

        ptr new_(new talk_to_svr(username));
        new_->start(ep);
        return new_;

    }
    void stop() {

        if ( !started_) return;
        started_ = false;
        sock_.close();

    }
    bool started() { return started_; }
    ...

private:
    size_t read_complete(const boost::system::error_code & err, size_t

bytes) {
        if ( err) return 0;

        bool found = std::find(read_buffer_, read_buffer_ + bytes,
'\n')

            < read_buffer_ + bytes;
        return found ? 0 : 1;