void client(io_service &ios, deadline_timer &timer, const system::error_code &ec){    try{        cout << "client start." << endl;        ip::tcp::socket _sock(ios);        ip::tcp::endpoint ep(ip::address::from_string("127.0.0.1"), 6688);        _sock.connect(ep);        vector<char> str(100, 0);        _sock.read_some(buffer(str));        cout << "recive from " << _sock.remote_endpoint().address();        cout << &str[0] << endl;        timer.async_wait(bind(client, ref(ios), ref(timer), placeholders::error));    }    catch(std::exception &e)    {        cout << e.what() << endl;    }}int main(int argc, _TCHAR* argv[]){    io_service ios;    deadline_timer timer(ios, posix_time::seconds(2));    timer.async_wait(bind(client, ref(ios), ref(timer), placeholders::error));    ios.run();    getchar();    return 0;}