Question

In the release version of my code one line is throwing an exception and I don’t know what type of exception it is so I can’t catch it correctly or figure out the problem.

I using the catch(…) but that’s pretty much worthless.

here is some pseudo code

 try
  {
    m_mmwIPC = gcnew NiftyIPC(gcnew String("Monitor"), true);
  }
  catch (CException* e)
  {
    TCHAR   szCause[255];
    e->GetErrorMessage(szCause, 255);
    CString errorStr = szCause;
    RemoveLineFeeds(errorStr);
    OutputDebugString(errorStr);
  }
  catch(...)
  {
    OutputDebugString(L"Unknown exception\n");
  }

So, is there any way to get any details on the thrown unknown exception? Just a type would be great.

thanks

Answer 1

Not really, it could be an int, a const char* or a RhubarbPie über-smart pointer.

However:

• Try catching std::exception too. That will catch a lot of C++ native exceptions.
• Your exception is probably a .NET one, so try to catch that one, not the MFC Base exception. (It looks like you’re doing C++/CLI. In that case, .NET-exceptions end up in the catch-all clause)
• Also, exceptions are usually meant to be caught by reference in C++
  (Update: MFC apparently uses throw-and-catch by pointer. That works too, as long as you catch what is thrown.)
• It might also help to use __try and __catch, since some “hardware” exceptions like stack-overflow, access violation, etc, are also unknown exceptions on Windows. The syntax for catching them are a bit differently, but you get an exception identifier that can be used to report the type of exception thrown. I use that to print stack-traces on fatal errors in our apps.