Question

Based on this SO answer: Catching COMException specific Error Code, I’d like to know, to properly handle COMExceptions across OSs and multiple versions of OL, if I need to only look at a specific portion of the exception. For example,

private const uint HRESULT_OPERATIONABORTED = 0x80004004;

// ...

    try {
        // something that could throw COMExceptions
    } catch (System.Runtime.InteropServices.COMException e) {

        switch ((uint)e.ErrorCode) {

            case HRESULT_OPERATIONABORTED:
                break;

            default:
                break;
        }
    }

Is this sufficiently cross-platform, or is it necessary to consider only a part of the error code?

EDIT – Just to clarify, my exact question is whether comparing (uint)e.ErrorCode to 0x80004004 is too specific (that is to say, whether or not I always get 0x80004004 for this particular error, regardless of OS/OL), or if this is the proper way to do things.

Answer 1

You have little to fear as far as cross-platform compat goes, COM only runs on Windows. Similarly, the error code is a well defined one. You can look up the standard COM error codes in the WinError.h SDK header file. It is E_ABORT. I’d recommend you actually use that identifier.

You’ll find this header in c:\program files\microsoft sdks\windows\v6.0\include. It is v7.0 for VS2010.