Question

我使用＆＃34;创建新线程方法＆＃34;处理新客户端并遇到UDP问题。首先，我使用主线程创建一个TCP线程来处理新的accept（）并创建一个UDP线程来处理新的recvfrom（）。（TCP案例还可以）一旦第一次recvfrom（）回调，我尝试将客户端传递给新的UDP线程，并保持当前的一个处理下一个新的UDP客户端应该通过将地址和新创建的数据报套接字传递给新线程来继续执行recvfrom（），对吗？

在实验过程中，我发现OLD UDP线程一直在从客户端接收数据报，而新线程正在执行while循环，recvfrom（）转为非阻塞方式，结果返回-1。

因此我的代码有什么问题....谢谢〜我是否理解错误？？

PassToUDPThread是我为传递给新线程的数据所做的结构类型：

typedef struct {
   sockaddr_in ReceiverSocket;
   SOCKET sendSocket;
   char* recvbuf;
   long packet_size;

}PassToUDPThread;

这是我的FIRST UDP线程函数的代码（仅处理第一个recvfrom（））：

sockaddr_in *ReceiverSocket = new sockaddr_in;

ReceiverSocket->sin_family = AF_INET;
if (strcmp(recv_hostname, "INADDR_ANY") != 0)
inet_pton(AF_INET, ip_addr_char, &ReceiverSocket->sin_addr.s_addr);
else ReceiverSocket->sin_addr.s_addr = INADDR_ANY;
ReceiverSocket->sin_port = htons((u_short)recv_port);

//*** Create the socket
SOCKET s;

s = socket(AF_INET, SOCK_DGRAM, 0);
printf("Receiver: Socket Created - UDP connection\n");
bind(s, (struct sockaddr *)ReceiverSocket, sizeof(struct sockaddr_in));

do
{
   int fromlen = (int)sizeof(struct sockaddr_in);
   retVal = recvfrom(s, recvbuf, packet_size, 0, (struct sockaddr*)ReceiverSocket, &fromlen);
   std::cout << "UDP recv by MAIN "<<std::endl;
   if (retVal == SOCKET_ERROR) {
      std::cout << "UDP Socket error : " + WSAGetLastError()<<std::endl;
      return 0;
   }
   else {
       SOCKET sendSocket = socket(AF_INET, SOCK_DGRAM, 0);
       PassToUDPThread _p;
       PassToUDPThread *p = &_p;
       p->sendSocket = sendSocket;
       p->ReceiverSocket = *ReceiverSocket;
       p->recvbuf = recvbuf;
       p->packet_size = packet_size;

       thrd_t UDPthread;
       if (thrd_create(&UDPthread, ThreadUDPReceiver, (void*)p) == thrd_success) {
           std::cout<<"success create new UDP thread"<<std::endl;
                            }




   }
   } while (retVal>0);
     closesocket(s);
     UDPReceiver(arg);
     return 1;
}

以下是NEW-CREATED UDP线程上的函数代码：

 int ThreadUDPReceiver(void *arg) {

    int retVal;
    SOCKET s = ((PassToUDPThread*)arg)->sendSocket;
    char* recvbuf = ((PassToUDPThread*)arg)->recvbuf;
    long packet_size = ((PassToUDPThread*)arg)->packet_size;
    sockaddr_in *ReceiverSocket = new sockaddr_in;
    memcpy(ReceiverSocket, &(((PassToUDPThread*)arg)->ReceiverSocket), sizeof sockaddr_in);

    bind(s, (struct sockaddr *)ReceiverSocket, sizeof(struct sockaddr_in));

    do {
       int fromlen = (int)sizeof(struct sockaddr_in);
       retVal = recvfrom(s, recvbuf, packet_size, 0, (struct sockaddr *)ReceiverSocket, &fromlen);
       std::cout << "UDP recv by thread "<< std::endl;
    } while (true);

    return 0;

    }

Answer 1

使用线程池。
摆脱额外的UDP套接字。使用相同的一个发送请求到达的响应。对客户来说也更简单。

通过C ++实现多线程并发服务器（UDP案例）

1 个答案: