如何为多线程客户端访问多个线程上的相同套接字

Question

我设置了一个多线程客户端，以便在一个线程上从服务器接收消息，而另一个线程等待用户输入以便向服务器发送消息。

我是新手，我的代码目前所做的是：两个线程都将单独连接到服务器，这使得服务器将单个客户端识别为两个客户端（因为两个线程都单独连接到服务器）。如何解决此问题，以便接收和发送连接使用相同的连接？

我已经包含了我的客户端代码的相关部分（通过函数connectToServer连接到服务器）

/*thread for sending messages to server*/
DWORD WINAPI send_handle_thread(LPVOID threadInfo)
{
/*structure contains all the data this callback works on*/
myThreadArgument* send_argument = (myThreadArgument*)threadInfo;

/*get client connection*/
myTcpSocket my_client(PORTNUM);

string server_ip_address = "";
readServerConfig(server_ip_address);

my_client.connectToServer(server_ip_address, ADDRESS); //this is where the thread connects to server

while (1)
{
    /*send messages*/

}
return 1;
}

/*thread for receiving messages from server*/
DWORD WINAPI rec_handle_thread(LPVOID threadInfo)
{
/*structure contains all the data this callback works on*/
myThreadArgument* send_argument = (myThreadArgument*)threadInfo;

/*get client connection*/
myTcpSocket my_client(PORTNUM);

string server_ip_address = "";
readServerConfig(server_ip_address);

my_client.connectToServer(server_ip_address, ADDRESS); //this is where thread connects to server

int rec_bytes = 0;

while (1)
{
    /*receive messages*/

}
return 1;
}

int main()
{
/*build a semaphore to synchronise access to std::cout*/
mySemaphore cout_semaphore(string(""),1);

/*initialize the winsock library*/
myTcpSocket::initialize();

/*get local (client) information (assume neither the name nor the address is given)*/
myHostInfo client_info;
string client_name = client_info.getHostName();
string client_ip_address = client_info.getHostIPAddress();

cout << "local host (client) information: " << endl;
cout << "   name:       " << client_name << endl;
cout << "   address:    " << client_ip_address << endl << endl;

/*retrieve server's IP name and address*/
string server_ip_address = "";
readServerConfig(server_ip_address);

myHostInfo server_info(server_ip_address, ADDRESS);
string server_name = server_info.getHostName();

cout << "remote host (server) information: " << endl;
cout << "   name:       " << server_name << endl;
cout << "   address:    " << server_ip_address << endl;

/*retrieve client's IP name and address*/
myTcpSocket my_client(PORTNUM);
cout << my_client;

/*create thread to send messages to server*/
myThreadArgument* send_argument = new myThreadArgument(&my_client, &cout_semaphore, client_name);
myThread* send_thread = new myThread(send_handle_thread, (void*)send_argument);
send_thread->execute();

/*create thread to receive message from server*/
myThreadArgument* rec_argument = new myThreadArgument(&my_client, &cout_semaphore, client_name);
myThread* rec_thread = new myThread(rec_handle_thread, (void*)rec_argument);
rec_thread->execute();

while (1)
{
    Sleep(300);
    cout << "main thread";
}

return 1;
}

connectToServer代码：

void myTcpSocket::connectToServer(string& serverNameOrAddr,hostType hType)
{ 
/* 
   when this method is called, a client socket has been built already,
   so we have the socketId and portNumber ready.

   a myHostInfo instance is created, no matter how the server's name is 
   given (such as www.yuchen.net) or the server's address is given (such
   as 169.56.32.35), we can use this myHostInfo instance to get the 
   IP address of the server
*/

myHostInfo serverInfo(serverNameOrAddr,hType);

// Store the IP address and socket port number  
struct sockaddr_in serverAddress;
serverAddress.sin_family = AF_INET;
serverAddress.sin_addr.s_addr = inet_addr(serverInfo.getHostIPAddress());
serverAddress.sin_port = htons(portNumber);

// Connect to the given address
try 
{
    if (connect(socketId,(struct sockaddr *)&serverAddress,sizeof(serverAddress)) == -1)
    {
        #ifdef WINDOWS_7 //XP
            int errorCode = 0;
            string errorMsg = "error calling connect():\n";
            detectErrorConnect(&errorCode,errorMsg);
            myException socketConnectException(errorCode,errorMsg);
            throw socketConnectException;
        #endif

        #ifdef UNIX
            myException unixSocketConnectException(0,"unix: error calling connect()");
            throw unixSocketConnectException;
        #endif
    }
}
catch(myException& excp)
{
    excp.response();
    exit(1);
}
}

Answer 1

只需在两个地方使用相同的套接字 FD。使用时甚至不需要同步。