Problems with sending cyrillic messages through socket

Question

I am trying to send cyrillic messages through socket and I have problem. The message doesn't go through. If I use char (on both sides), on the other side I receive, the cyrilic part incorrect. If I use WCHAR (on both sides), I receive the message until the first cyrillic character. If I send only ASCII characters everything is ok. So here is the client code. If it is necessary I can put the server code as well.

Client:

  char ip_addr[] = "192.168.0.102";
  int port = 30000;
  wchar_t message[] = L"TEST ТЕСТ MESSAGE ПОРАКА";
  //char message[] = "TEST ТЕСТ MESSAGE ПОРАКА";
  WSADATA wsaData;
  int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
  if (iResult != 0) {
    wprintf(L"WSAStartup failed: %d\n", iResult);
    return 1;
  }

  struct sockaddr_in messageServer;
  memset(&messageServer, 0, sizeof(messageServer));
  messageServer.sin_family = AF_INET;
  messageServer.sin_addr.S_un.S_addr = inet_addr(ip_addr);
  messageServer.sin_port = htons(port);
  SOCKET outsocket;
  outsocket = socket(AF_INET, SOCK_STREAM, 0);

  if (outsocket == -1) {
    std::cout << "ERROR";
    exit(-1);
  }

  int connRes = 0;
  connRes = connect(outsocket, (struct sockaddr *)&messageServer, sizeof(messageServer));
  if (connRes < 0) {
    std::cout << "ERRROR CONNECT " << WSAGetLastError() <<  std::endl;
    system("pause");
    exit(-1);
  }

  int result;
  result = send(outsocket, (char*)message, sizeof(message), 0);
  if (result == SOCKET_ERROR) {
    wprintf(L"send failed with error: %d\n", WSAGetLastError());
    closesocket(outsocket);
    WSACleanup();
    return 1;
  } else {
    std::wcout << "Return code: " << result << std::endl;
  }
  closesocket(clientSocket);

Server:

  int port = 30000;
  char ip_addr[] = "192.168.0.102";
  struct sockaddr_in serverAddr, clientAddr;

  memset(&serverAddr, 0, sizeof(serverAddr));
  memset(&clientAddr, 0, sizeof(clientAddr));

  std::locale::global(std::locale("Russian_Russia"));

  WSADATA wsaData;
  int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);
  if (iResult != NO_ERROR) {
    wprintf(L"Error at WSAStartup()\n");
    return 1;
  }

  serverAddr.sin_family = AF_INET;
  serverAddr.sin_addr.S_un.S_addr = inet_addr(ip_addr);
  serverAddr.sin_port = htons(port);

  SOCKET serverSocket = socket(AF_INET, SOCK_STREAM, 0);
  int bindRes = 0;
  bindRes = bind(serverSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));
  if (bindRes < 0) {
    std::wcout << "ERRROR BIND" << WSAGetLastError() <<  std::endl;
    system("pause");
    exit(-1);
  }

  if (listen(serverSocket, 5) < 0)
  {
    std::wcout << "ERRRORRR LISTEN" << std::endl;
    system("pause");
    exit(-1);
  }

  for (;;)
  {
    std::wcout << "WAITING..." << std::endl;
    int length = sizeof(clientAddr);

    wchar_t message[500];
    ZeroMemory(&message, sizeof(message));
    SOCKET clientSocket = accept(serverSocket, (struct sockaddr *) &clientAddr, &length);
    int bR = 0;
    bR = recv(clientSocket, (char*)message, sizeof(message), 0);
    if(bR == -1) {
      std::wcout << "ERRRRORORORORRR";
    }

    std::wcout << "Received bytes: " << bR << std::endl;
    std::wcout << "Message: " << message << std::endl;

    closesocket(clientSocket);
  }

I have also made a capture with Wireshark. And here is the output: HEX:

54:00:45:00:53:00:54:00:20:00:22:04:15:04:21:04:22:04:20:00:4d:00:45:00:53:00:53:00:41:00:47:00:45:00:20:00:1f:04:1e:04:20:04:10:04:1a:04:10:04:00:00:cc

TEST "!" MESSAGE

Answer 1

Based on what you posted its kind of hard to tell what is wrong.

First of all, the usual problem, recv / send may not give you the data you asked for since it's just a hint. What makes it more confusing that on localhost it succeeds almost all the time meaning that send will most likely send the data in one call and recv will receive it in one call.

Take a look at recv and send especially the remarks section about the buffer and it's length.

Secondly, strings are generally don't behave well when sent over the network, assuming that the server part is also windows it may work but still, you have to make sure you always send based on char count * char size for ASCII char size is 1 Byte for unicode it is 2 Bytes for windows but linux used 4 Bytes thus you have to make sure you know how long is your string then calculate it's size in bytes. On top of all this you have to make sure you know where your data ends, for both send and the string displaying functions that is usually a '\0' but you can let the network function know how long it actually is before sending the string data and when the data is recvd then you manually put a null '\0' at the end.

So based on what you posted it should work because C automatically adds a \0 at the end of each static string, and since you run this on localhost the send/recv should also work, so you either have a network problem or something else is wrong. Post more info if you can since it hard to tell just from this what could be wrong.