CODEWITHSUNDEEP
c#c++log4net
anti
anti

Reputation: 3125

Log4net, sending log messages from a c++ dll to a c# application?

I have a WPF / c# application that uses Log4Net for logging. This application calls a few c++ dlls using:

[DllImport("test.dll", CallingConvention = CallingConvention.Cdecl)] public static extern void TestFunction();

What I would like to do is have the dlls send logging messages back to the C# application, so that everything from both c++ and c# go to the same log. Is this possible?

If so, how can i go about it?

Upvotes: 3

Views: 829

Answers (1)

heLomaN
heLomaN

Reputation: 1794

An example that redirect logs in c++ dill to c# callback:

c# side:

[UnmanagedFunctionPointer(CallingConvention.StdCall)]
delegate void LogCallback([MarshalAs(UnmanagedType.LPWStr)] string info);

namespace WinApp
{
  static class Wrapper
  {
    [DllImport("target.dll", CharSet = CharSet.Unicode, CallingConvention = CallingConvention.Cdecl)]
    public static extern void SetLogCallback([MarshalAs(UnmanagedType.FunctionPtr)] LogCallback callbackPointer);

    internal static void Init()
    {
      LogCallback log_cb = (info) =>
      {
        Console.Write(DateTime.Now.TimeOfDay.ToString() + " " + info);
      };
      SetLogCallback(log_cb);
    }
  }

c++ side( compiled in target.dll):

extern "C" {
    typedef char* (__stdcall* LogCallback)(const wchar_t* info);
    PEPARSER_API void SetLogCallback(LogCallback cb);
}

static LogCallback global_log_cb = nullptr;


void LogInfo(const wchar_t* info) {
    if (global_log_cb) {
        std::wstring buf = L"[PEParse]" + std::wstring(info) + L"\n";
        global_log_cb(buf.c_str());
    }
    else {
        std::cout << "global_log_cb not set\n";
    }
}

void LogInfo(const char* info) {
    const size_t cSize = strlen(info) + 1;

    size_t t;

    std::wstring wstr(cSize, L'#');
    mbstowcs_s(&t, &wstr[0], cSize, info, cSize - 1);

    LogInfo(&wstr[0]);
}

void SetLogCallback(LogCallback cb) {
    global_log_cb = cb;
    LogInfo("log init");
}

I have been using this interface for long times.

Upvotes: 3

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