setsockopts() / SO_KEEPALIVE support for servers?

[rolfk]

---

@AllenHuffman wrote:

After adding the .lib to the project, I now get an error that using this library is only available in the "Full Development System." Indeed, my install says Base.

Am I completely out-of-luck at using WIN32 APIs with my version?

---

Well I suppose you could always link to that function yourself. It's not something you want to do for a large amount of functions but for one single function should be no problem.

typedef int (WSAAPI *WSAIoctlPtr)(
  SOCKET                             s,
  DWORD                              dwIoControlCode,
  LPVOID                             lpvInBuffer,
  DWORD                              cbInBuffer,
  LPVOID                             lpvOutBuffer,
  DWORD                              cbOutBuffer,
  LPDWORD                            lpcbBytesReturned,
  LPWSAOVERLAPPED                    lpOverlapped,
  LPWSAOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine
);

int WSAAPI WSAIoctlFunc(
  SOCKET                             s,
  DWORD                              dwIoControlCode,
  LPVOID                             lpvInBuffer,
  DWORD                              cbInBuffer,
  LPVOID                             lpvOutBuffer,
  DWORD                              cbOutBuffer,
  LPDWORD                            lpcbBytesReturned,
  LPWSAOVERLAPPED                    lpOverlapped,
  LPWSAOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine
)
{
    HMODULE handle = LoadLibrary("ws2_32.dll");
    if (handle)
    {
        WSAIoctlPtr func = (WSAIoctlPtr)GetProcAddress(handle, "WSAIoctl");
        FreeLibrary(handle);
        if (func)
            return func(s, dwIoControlCode, lpvInBuffer, cbInBuffer, lpvOutBuffer, cbOutBuffer, lpcbBytesReturned,  lpOverlapped, lpCompletionRoutine);
    }
    return WSASYSNOTREADY;
}

[AllenHuffman]

@rolfk wrote:

Well I suppose you could always link to that function yourself. It's not something you want to do for a large amount of functions but for one single function should be no problem.

Thanks for that -- good trick to know.

[AllenHuffman]

I am unable to work on this project at the moment, but it looks like using a timer and "DisconnectTCPClient()" might also do the trick, assuming the server is then available and ready for another connection.

The issue is if a remote client goes away (cable pull, power off, etc.) and no TCP_DISCONNECT is seen, the code sits there "forever" (?). It shouldn't do that, so plan to fix that.

[AllenHuffman]

Since my goal was to disconnect a listening server (in case something happened to the remote Client and no Disconnect was sent), I ended up using a Timer. In the handler, I'd increment a counter, which I reset on any new connection (we only allow one at a time) or any time TCP data comes in. If that counter hits a threshold (X seconds), I used the Client TCP Disconnect call to force close. Then the server will recycle. This works fine for what I needed to do.