c++ - Boost 客户端卡住

Question

http://www.boost.org/doc/libs/1_46_0/doc/html/boost_asio/example/chat/chat_client.cpp

我正在根据上面的示例开发客户端应用程序。

我想在单独的线程中进行客户端连接，这样 UI 就不会卡住。这里 UI 卡住了。
1. 你能告诉我如何实现吗？
2.这一行是什么意思？ boost::thread t(boost::bind(&boost::asio::io_service::run, &io_service));
t.join();
此行是否为连接创建了单独的线程？

 client::client(boost::asio::io_service& io_service, tcp::resolver::iterator endpoint_iterator)
  : io_service_(io_service),
  resolver_(io_service),
  socket_(io_service_)
{
    tcp::endpoint endpoint = *endpoint_iterator;
    socket_.async_connect(  endpoint,
                                 boost::bind(&client::handle_connect, this,boost::asio::placeholders::error,
                            ++endpoint_iterator));

}
void client::handle_connect(const boost::system::error_code& error,
  tcp::resolver::iterator endpoint_iterator)
{
  strcpy(data_,"Hello");
if (!error)
{
     /*boost::asio::async_read(socket_,
                              boost::asio::buffer(data_, MAX_PATH),
                              boost::bind(&client::handle_read, this,
                              boost::asio::placeholders::error));*/
      boost::asio::async_write(socket_,  boost::asio::buffer(data_, MAX_PATH),
                               boost::bind(&client::handle_read, this,
                            boost::asio::placeholders::error));
}
else if (endpoint_iterator != tcp::resolver::iterator())
{
  socket_.close();
  tcp::endpoint endpoint = *endpoint_iterator;
  socket_.async_connect(    endpoint,
                            boost::bind(&client::handle_connect, this,
                            boost::asio::placeholders::error, ++endpoint_iterator));
}
}

void client::handle_read(const boost::system::error_code& error)
{
if (!error)
{  
     memset(data_,0,MAX_PATH);
     boost::asio::async_read(   socket_,
                                 boost::asio::buffer(data_, MAX_PATH),
                              boost::bind(&client::handle_read, this,
                              boost::asio::placeholders::error));

     if (strcmp(data_,"Hello Response")==0)
     {
         MessageBox(NULL,_T("Regd Done"),_T("Vue"),1);
        // return ;
     }  


}

}

CConnectionMgr::CConnectionMgr(void)
{

}
void CConnectionMgr::Connect()
{
try
{
    char* host = "192.168.4.84";
    char* port = "55555";
    boost::asio::io_service io_service;

    tcp::resolver resolver(io_service);
    tcp::resolver::query query(tcp::v4(),host , port);
    tcp::resolver::iterator iterator = resolver.resolve(query);

    c = new client(io_service, iterator);

    //boost::thread thrd(boost::bind(&boost::asio::io_service::run, &io_service));
    boost::thread t(boost::bind(&boost::asio::io_service::run, &io_service));
    t.join();
    // MessageBox(NULL,_T("Join"),_T("ff"),1);
}
catch (std::exception& e)
{
  CString csMsg(e.what());
  MessageBox(NULL,csMsg,_T("ff"),1);    
 }
 }

Answer 1

“t.join()”等待线程“t”退出。线程 't' 正在 io_service 上运行 run() 方法，当没有剩余的 I/O 需要完成时将退出。

因此，您的 Connect() 方法将阻塞，直到所有 I/O 完成，这显然不是您想要的。如果您打算执行异步 I/O 以便您的客户端不会阻塞，您需要为您的 I/O 上下文设计一种方式来与我们的 UI 上下文进行通信。这不会靠魔法发生。