C++ socket select（）函數返回0與許多連接

我有一個代碼，其中服務器發送一個UDP消息，其中包含一個TCP端口號給客戶端。然後服務器等待與客戶端的傳入TCP連接。但是，select（）函數返回多個連接的超時值。我可以弄清楚可能是什麼問題。C++ socket select（）函數返回0與許多連接

對以下代碼的任何幫助和意見都非常感謝。預先感謝您的幫助。

void initialise(void) 
{ 

    m_tcp_listensocket = getlistensocket(); 
    highsock = m_tcp_listensocket; 

    setnonblocking(m_tcp_listensocket); 
    struct timeval timeout; 
    timeout.tv_sec = m_timeout; 
    timeout.tv_usec = 0; 


    // Send UDP messages to clients not connected 
    for (int i = 0; i < UDP_Connections.size(); i++) 
    { 
     // Only to clients not connected 
     if (TCP_Connections[i]->IsConnected()) 
     { 
     continue; 
     } 

     // making the message: 'server_address:server_port'. 
     char l_str_server_port_number[6]; 
     sprintf (l_str_server_port_number, "%d", TCP_Connections[i]->get_server_port_number()); 

     struct hostent *host; 

    if((host = gethostbyname(m_host_name)) == NULL) 
    { 

     // gethostbyname() made error 
    }  
     struct in_addr MyAddress; 
     memcpy(&MyAddress.s_addr, host->h_addr_list[0], sizeof(MyAddress.s_addr)); 

     std::string l_str_init_message = std::string(l_str_server_port_number) + "\0"; 

     UDP_Connections[i]->sendUDPMessage(l_str_init_message.c_str()); 
    } 

    for (int i = 0; i < TCP_Connections.size(); i++) 
    { 
     struct sockaddr_in clientaddr; 
     bzero(&clientaddr, sizeof(clientaddr)); 
     clientaddr.sin_family = AF_INET; 
     clientaddr.sin_addr.s_addr = htonl(INADDR_ANY); 

     fd_set readSet; 
     FD_ZERO(&readSet); 
     FD_SET(m_tcp_listensocket, &readSet); 

     int readsocks = select(highsock+1, &readSet, NULL, NULL, &timeout); 

     switch (readsocks) 
    { 
    case 0: 
     /* timeout */ 
     break; 

    case -1: 
     /* error */ 
     break; 

    default: 
     if (FD_ISSET (m_tcp_listensocket, &readSet)) 
     { 
      socklen_t tempo = (socklen_t)sizeof(clientaddr); 

      int l_Socket = accept(m_tcp_listensocket, (struct sockaddr *)&clientaddr, &tempo); 
      if (l_Socket > highsock) 
     highsock = l_Socket; 

      if (l_Socket >= 0) 
     { 
      // connection accepted 

      char adr[16] ; 
      inet_ntop(PF_INET,&clientaddr.sin_addr, adr, sizeof(adr)); 

      for (int j= 0; j < UDP_Connections.size(); j++) 
      { 

       if (UDP_Connections[j]->get_clientIP() == (std::string)adr) 
      {  
       TCP_Connections[j]->set_TCPsocket(l_Socket); 
       break; 
      } 
      } 

     } 
      else 
     { 
      // socket error 
     } 
     } 
    } 
    } 
}

來源

2011-02-09 user609823

select()更新他們的超時參數的某些實現，可能需要在每次調用前重置此。

來源

2011-02-09 14:27:15 Hasturkun

謝謝你的回答。這是需要注意的一點，但它不能解決問題。當許多客戶端嘗試建立TCP連接時，select（）會返回超時值。 – user609823 2011-02-14 20:55:47

C++ socket select（）函數返回0與許多連接

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