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我在使用 async_read_some 时遇到了困难

我用 async_write_some 编译并成功了。

但是，我尝试使用 async_read_some 进行编译，

并提出了奇怪的错误，它可以找到正确的方法。

我是提升世界的新手。请帮我解决这些问题。

提前致谢。

opps编译错误是这样的

错误：没有匹配函数调用 'ws_async_tcp_connection::async_recv_msg_some(boost::asio::mutable_buffers_1, boost::_bi::bind_t, boost::_bi::list3, boost::arg<1> ( )(), boost::arg<2> ( )()> >)' /home/chris/proto/inc/ws_async_tcp_connection.h:119: 注意：候选者是：void ws_async_tcp_connection::async_recv_msg_some(T&, Handler) [with T = boost ::asio::mutable_buffers_1, 处理程序 = boost::_bi::bind_t, boost::_bi::list3, boost::arg<1> ( )(), boost::arg<2> ( )()> > ]

header 
-----------------------------------------------------------------------------------
class ws_async_tcp_connection{
    boost::asio::ip::tcp::socket socket_;
public:

    ws_async_tcp_connection(boost::asio::io_service& arg_io_service)
        : socket_(arg_io_service){}


    /*
    *   destructor
    */      
    ~ws_async_tcp_connection(){
        shutdown();
    }


    /*
    *   connect method
    *       : binding connection handler -> handle_connect
    */
    void connect(const std::string& host_addr, const std::string& port_no){
        boost::asio::ip::tcp::resolver resolver_(socket_.get_io_service());
        boost::asio::ip::tcp::resolver::query query_(boost::asio::ip::tcp::v4(), host_addr, port_no);
        boost::asio::ip::tcp::resolver::iterator end_point_iter = resolver_.resolve(query_);
        boost::asio::async_connect(socket_, end_point_iter, 
            boost::bind(&ws_async_tcp_connection::handle_connect, this, boost::asio::placeholders::error));
    }


    /*
    *   handle_connect
    *       : handle after the connect method called
    */
    void handle_connect(const boost::system::error_code& ec){
        if(!ec){
            // successfully established the connection - maybe print the remote ip, port
            /*  getting the remote_endpoint ip, port
            std::string connected_server_ip = socket_.remote_endpoint().address().to_string();
            unsigned short connected_server_port = socket_.remote_endpoint().port();
            */
        }
        else{
            // error handling - maybe use Logger class to print the error
            shutdown();
        }
    }


    /*
    *   set_option
    *       : set option for the tcp socket
    */
    template<typename SettableSocketOption>
    void set_option(const SettableSocketOption& option){
        // if performance is poor, then let's try no_delay option(true);
        /* keepalive option
            boost::asio::socket_base::keep_alive option(true);
            socket.set_option(option);
        */
        socket_.set_option(option);
    }


    /*
    *   is_open
    *       : socket is opened or not
    */
    bool is_open(){
        return socket_.is_open();
    }

    /*
    *   async_send_msg
    *       : send msg (warning! : will be blocked until the exact bytes you ask for are transmitted)
    */
    template <typename T, typename Handler> 
    void async_send_msg(const T& send_buf, Handler handler){
        boost::asio::async_write(socket_, send_buf, handler);
    }


    /*
    *   async_recv_msg
    *       : recv msg (warning! : will be blocked until the exact bytes you ask for are transmitted)
    */
    template <typename T, typename Handler> 
    void async_recv_msg(T& recv_buf, Handler handler){
        boost::asio::async_read(socket_, recv_buf, handler);
    }

    /*
    *   async_send_msg_some
    *       : send msg
    */  
    template <typename T, typename Handler> 
    void async_send_msg_some(const T& send_buf, Handler handler){
        socket_.async_write_some(send_buf, handler);
    }


    /*
    *   async_recv_msg_some
    *       : recv msg (Typically use this if you don't have to receive the exact numbers of bytes)
    */
    template <typename T, typename Handler> 
    void async_recv_msg_some(T& recv_buf, Handler handler){
        socket_.async_read_some(recv_buf, handler);
    }


    /*
    *   shutdown
    */
    void shutdown(){
        if(is_open()){
            boost::system::error_code ec;
            socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
            if(ec){
                // may print shutdown error
            }
            socket_.close();
        }
    }

    /*
    *   socket
    *       : returning the current holding socket
    */
    boost::asio::ip::tcp::socket& socket(){
        return socket_;
    }
};

typedef boost::shared_ptr<ws_async_tcp_connection> async_tcp_ptr;


-------------------------------------------------------------------------------
src
-------------------------------------------------------------------------------

class async_tcp_test_server{
    enum{ buf_size = 1024 };
    boost::asio::ip::tcp::acceptor acceptor_;
    boost::array<char, buf_size> send_buf;
    boost::array<char, buf_size> recv_buf;
public:
    async_tcp_test_server(boost::asio::io_service& io_service, unsigned short port_no)
        : acceptor_(io_service, boost::asio::ip::tcp::endpoint(boost::asio::ip::tcp::v4(), port_no)){

        // start an accept operation for a new connection
        async_tcp_ptr new_conn(new ws_async_tcp_connection(acceptor_.get_io_service()));
        acceptor_.async_accept(new_conn->socket(), boost::bind(&async_tcp_test_server::handle_accept, this,
            boost::asio::placeholders::error, new_conn));
    }

    void handle_accept(const boost::system::error_code& ec, async_tcp_ptr conn){

        if(!ec){
            send_buf.assign(0x00);
            string hello_str = "Welcome to connect Asynchronous TCP Test Server :)";
            memcpy(&send_buf[0], hello_str.c_str(), hello_str.length());
            conn->async_send_msg(boost::asio::buffer(send_buf), boost::bind(&async_tcp_test_server::handle_write, this, boost::asio::placeholders::error, conn));
            //conn->async_send_msg_some(boost::asio::buffer(send_buf), boost::bind(&async_tcp_test_server::handle_write, this, boost::asio::placeholders::error, 
                //boost::asio::placeholders::bytes_transferred, conn));
        }

        // start an accept operation for new connection
        async_tcp_ptr new_conn(new ws_async_tcp_connection(acceptor_.get_io_service()));
        acceptor_.async_accept(new_conn->socket(), boost::bind(&async_tcp_test_server::handle_accept, this,
            boost::asio::placeholders::error, new_conn));
    }


    void handle_write(const boost::system::error_code& ec, async_tcp_ptr conn){
        if(!ec){
            recv_buf.assign(0x00);
            conn->async_recv_msg_some(boost::asio::buffer(recv_buf), boost::bind(&async_tcp_test_server::handle_read, this, boost::asio::placeholders::error, 
                boost::asio::placeholders::bytes_transferred));
        }
    }


    void handle_read(const boost::system::error_code& ec, size_t num_recv_bytes){
        cout << recv_buf.data() << endl;
    }
};


int main(void)
{
    unsigned short port_no = 7807;
    boost::asio::io_service io_svr;
    async_tcp_test_server test_server(io_svr, port_no);
    io_svr.run();
}

这是错误的输出（在我更改了 T& -> const T& 之后）

/home/chris/proto/boost/boost/bind/bind_template.hpp:15: 从 'boost::_bi::bind_t, boost::arg<1> ( )(), boost::arg<2> ( )(), boost::_bi::value > > >' async_tcp_test_server.cpp:46: 从这里实例化 /home/chris/proto/boost/boost/bind/bind.hpp:69: 错误: 'void (async_tcp_test_server: :*)(const boost::system::error_code&, size_t)' 不是类、结构或联合类型 /home/chris/proto/boost/boost/asio/basic_stream_socket.hpp：在成员函数 'void boost: :asio::basic_stream_socket::async_read_some(const MutableBufferSequence&, const ReadHandler&) [with MutableBufferSequence = boost::asio::mutable_buffers_1, ReadHandler = boost::_bi::bind_t, boost::arg<1> ( )(), boost ::arg<2> ()(), boost::_bi::value > > >, 协议 = boost::asio::ip::tcp, StreamSocketService = boost::asio::stream_socket_service]': /home/chris/proto/inc/ws_async_tcp_connection .h:120：从 'void ws_async_tcp_connection::async_recv_msg_some(const T&, Handler) 实例化 [with T = boost::asio::mutable_buffers_1, Handler = boost::_bi::bind_t, boost::arg<1> ( ) (), boost::arg<2> ( )(), boost::_bi::value > > >]' async_tcp_test_server.cpp:46: 从这里实例化 /home/chris/proto/boost/boost/asio/basic_stream_socket .hpp:785：错误：不匹配调用 '(boost::_bi::bind_t, boost::arg<1> ( )(), boost::arg<2> ()(), boost::_bi::value > > >) (const boost::system::error_code&, const long unsigned int&)' /home/chris/proto/boost/boost/asio/detail/bind_handler.hpp:在成员函数 'void boost::asio::detail::binder2::operator()() [with Handler = boost::_bi::bind_t, boost::arg<1> ( )(), boost::arg <2> ( )(), boost::_bi::value > > >, Arg1 = boost::system::error_code, Arg2 = long unsigned int]': /home/chris/proto/boost/boost/asio/ handler_invoke_hook.hpp:64: 实例化自 'void boost::asio::asio_handler_invoke(Function, ...) [with Function = boost::asio::detail::binder2, boost::arg<1> ( )() , 升压::arg<2> ()(), boost::_bi::value > > >, boost::system::error_code, long unsigned int>]' /home/chris/proto/boost/boost/asio/detail/handler_invoke_helpers.hpp:39:从 'void boost_asio_handler_invoke_helpers::invoke(Function&, Context&) 实例化 [with Function = boost::asio::detail::binder2, boost::arg<1> ( )(), boost::arg<2> ( )( ), boost::_bi::value > > >, boost::system::error_code, long unsigned int>, 上下文 = boost::_bi::bind_t, boost::arg<1> ( )(), boost: :arg<2> ()(), boost::_bi::value > > >]' /home/chris/proto/boost/boost/asio/detail/reactive_socket_recv_op.hpp:110: 实例化自 'static void boost::asio::detail: :reactive_socket_recv_op::do_complete(boost::asio::detail::io_service_impl*, boost::asio::detail::operation*, const boost::system::error_code&, size_t) [with MutableBufferSequence = boost::asio: :mutable_buffers_1, 处理程序 = boost::_bi::bind_t, boost::arg<1> ( )(), boost::arg<2> ()(), boost::_bi::value > > >]' /home/chris/proto/boost/boost/asio/detail/reactive_socket_recv_op.hpp:80: 从 'boost::asio::detail::reactive_socket_recv_op 实例化::reactive_socket_recv_op(boost::asio::detail::socket_type, boost::asio::detail::socket_ops::state_type, const MutableBufferSequence&, int, Handler&) [with MutableBufferSequence = boost::asio::mutable_buffers_1, Handler = boost::_bi::bind_t, boost::arg<1> ( )(), boost::arg<2> ()(), boost::_bi::value > > >]' /home/chris/proto/boost/boost/asio/detail/reactive_socket_service_base.hpp:273: 从 'void boost::asio::detail:: 实例化reactive_socket_service_base::async_receive(boost::asio::detail::reactive_socket_service_base::base_implementation_type&, const MutableBufferSequence&, int, Handler) [with MutableBufferSequence = boost::asio::mutable_buffers_1, Handler = boost::_bi::bind_t, boost: :arg<1> ( )(), boost::arg<2> ()(), boost::_bi::value > > >]' /home/chris/proto/boost/boost/asio/stream_socket_service.hpp:318: 从'void boost::asio::stream_socket_service::async_receive(类型名 boost::asio::detail::reactive_socket_service::implementation_type&, const MutableBufferSequence&, int, const ReadHandler&) [with MutableBufferSequence = boost::asio::mutable_buffers_1, ReadHandler = boost::_bi::bind_t, boost::arg< 1> ( )(), boost::arg<2> ( )(), boost::_bi::value > > >, 协议 = boost::asio::ip::tcp]' /home/chris/proto /boost/boost/asio/basic_stream_socket.hpp:787: 实例化自 'void boost::asio::basic_stream_socket::async_read_some(const MutableBufferSequence&, const ReadHandler&) [with MutableBufferSequence = boost::asio::mutable_buffers_1,ReadHandler = boost::_bi::bind_t, boost::arg<1> ()(), boost::arg<2> ( )(), boost::_bi::value > > >, 协议 = boost::asio::ip::tcp, StreamSocketService = boost::asio::stream_socket_service] ' /home/chris/proto/inc/ws_async_tcp_connection.h:120: 实例化自 'void ws_async_tcp_connection::async_recv_msg_some(const T&, Handler) [with T = boost::asio::mutable_buffers_1, Handler = boost::_bi:: bind_t, boost::arg<1> ( )(), boost::arg<2> ( )(), boost::_bi::value > > >]' async_tcp_test_server.cpp:46: 从这里 /home/ 实例化chris/proto/boost/boost/asio/detail/bind_handler.hpp:118：错误：不匹配调用 '(boost::_bi::bind_t, boost::arg<1> ( )(), boost:: arg<2> ( )(), boost::_bi::value

4

1 回答 1

2

As the compiler said, the function you're calling expects a non-const reference to a buffer: async_recv_msg_some(T&, ... [with T = boost::asio::mutable_buffers_1

You're passing a buffer by value: async_recv_msg_some(boost::asio::mutable_buffers_1, because you created it as a temporary object with the rvalue expression boost::asio::buffer(recv_buf).

You'll have to change your function signature to either take T or const T& (I would go with const T&, because that's what async_read_some takes, and your function is just forwarding to that)

于 2012-12-21T02:14:42.733 回答