void main()  {      CInitSock initSock;      USHORT nPort = 9999; //监听的端口      SOCKET sListen = ::socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);      if (sListen == INVALID_SOCKET)      {          printf("socket error...");          return;      }      sockaddr_in servAddr = {0};      servAddr.sin_family = AF_INET;      servAddr.sin_port = ::htons(nPort);      servAddr.sin_addr.S_un.S_addr = INADDR_ANY;       if (SOCKET_ERROR == ::bind(sListen, (sockaddr*)&servAddr, sizeof(servAddr)))      {          int nError = ::GetLastError();          printf("connect error..");          return;      }      ::listen(sListen, 5);              //select模型处理过程      //1.初始化套接字集合，添加监听socket到这个集合      fd_set  fdSocket;      FD_ZERO(&fdSocket);      FD_SET(sListen, &fdSocket);      while (TRUE)      {          //2. 将集合的一个拷贝传递给select函数          //当有事件发生时，select移除未决的socket,然后返回   就是说select返回时 集合的中socket就是发生事件的socket          fd_set fdRead = fdSocket;          int nRet = ::select(0, &fdRead, NULL, NULL, NULL);          if (nRet > 0)          {              //通过比较原来的fdSocket集合与经过处理的fdRead集合              for (UINT i=0;i<fdSocket.fd_count;i++)              {                  if (FD_ISSET(fdSocket.fd_array[i], &fdRead)) //就是这个触发了                  {                      if (fdSocket.fd_array[i] == sListen) //监听套接字接收到新连接  为神马分两种情况：因为触发Read集合的情况有两种：有连接来了或数据可读了....                      {                          //                          if (fdSocket.fd_count < FD_SETSIZE) //FD_SETSIZE=64                          {                              sockaddr_in addrRemote = {0};                              int nAddrLen = sizeof(addrRemote);                              SOCKET sNew = ::accept(sListen, (sockaddr*)&addrRemote, &nAddrLen);                              FD_SET(sNew, &fdSocket);                          }                          else                              {                              printf("too many connection...error");                              continue;                          }                      }                      else  //有可读的                      {                          char szContent[256]={0};                          int nRecv = ::recv(fdSocket.fd_array[i], szContent, sizeof(szContent), 0);                          if (nRecv > 0)                          {                              szContent[nRecv] = '\0';                              printf("recv data:%s", szContent);                          }                          else //没读到数据                          {                              ::closesocket(fdSocket.fd_array[i]);                              FD_CLR(fdSocket.fd_array[i], &fdSocket);                          }                      }                  }              }          }          else          {              printf("nRet litter 0, error...");              return;          }      }      ::closesocket(sListen); //与socket配对写      printf("*******************************");      getchar();  }