Exceptions in COM and a managed consumer

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COM

I'm using a book, "insisde c#" by archer and whitechapel for some self-education. It may not be the very latest, but it's all I have at the moment. I'm trying to create an Error object in a COM component that the RCW will translate into a COMException in a managed consumer, like a C# program. Part of it seems to work - the ErrorCode. The message doesn't. I get "Invalid pointer <exception from HRESULT 0x8....5>" instead of the actual message.

I've scoured the net looking for info on the Error Object, the first parameter, and COMException, but there doesn't seem to be much. At least not enough to explain the "invalid pointer..." message. Any help - thanks in advance.

In my COM component:

return Error(LPCSTR(
    _T("Airline Timings not available for this Airline" )),
    __uuidof(AirlineInfo), AirlineError);

In my C# consumer:

catch (COMException e)
{
    Console.WriteLine("Oops, an error occured!"; +
       "Error Code is: {0}. Error message is : {1}",
        e.ErrorCode, e.Message);
}