if (!SetSelect(hWnd, FD_CONNECT))

              return (FALSE);

       SetSelect()主要就是调用WSAASyncSelect(),让Windows Sockets DLL在侦测到连接建立时,就发送一条UM_SOCK的自定义消息,使消息循环继续下去.如下:

       BOOL SetSelect(HWND hWnd, long lEvent)

       {

              if (WSAAsyncSelect(s, hWnd, UM_SOCK, lEvent) == SOCKET_ERROR)

              {

                     AlertUser(hWnd, "WSAAsyncSelect Failure.");

                     return (FALSE);