ATL inheritance mistake

From:

Barzo <dbarzo@gmail.com>

Newsgroups:

microsoft.public.vc.atl

Date:

Wed, 9 Dec 2009 08:28:36 -0800 (PST)

Message-ID:

<c17a6f7b-35c4-4c27-aaa6-0b91792038e0@u7g2000yqm.googlegroups.com>

Hi,

in my project I have to code this situation:

AudioDevice : public IAudioDevice;
CAudioRecorder : public AudioDevice, public IAudioRecorder;
CAudioDecoder : public CAudioRecorder, public IAudioDecoder

The IDL file that represent this situation is:

/////////////////////////////////////////////////////////////////

[
    object,
    uuid(AB566C6C-AF54-11DE-B5BE-00A0D15E9B20),
    oleautomation,
    nonextensible,
    helpstring("IAudioDevice Interface"),
    pointer_default(unique)
]
interface IAudioDevice : IUnknown
{
.....
}

[
    object,
    uuid(AB566C6E-AF54-11DE-B5BE-00A0D15E9B20),
  dual,
    oleautomation,
    nonextensible,
    helpstring("Dual interface for AudioRecorder objects"),
    pointer_default(unique)
]
interface IAudioRecorder : IDispatch
{
  ......
}

[
  uuid(AB566C76-AF54-11DE-B5BE-00A0D15E9B20),
  dual,
  nonextensible,
  helpstring("Dual interface for AudioDecoder objects"),
  hidden
]
interface IAudioDecoder : IDispatch
{
  [propget, id(40), helpstring("Returns a reference to a
IAudioRecorder interface.")]
  HRESULT Recorder([out, retval] IAudioRecorder** pVal);
  [propget, id(41), helpstring("Returns a reference to a IAudioDevice
interface.")]
  HRESULT Device([out, retval] IAudioDevice** pVal);
};

[
    uuid(AB566C66-AF54-11DE-B5BE-00A0D15E9B20),
    version(1.1),
    helpstring("Audio Library")
]
library AxAudioLib4
{
    importlib("stdole2.tlb");

    [
        uuid(AB566C74-AF54-11DE-B5BE-00A0D15E9B20),
        helpstring("AudioRecorder Class")
    ]
    coclass AudioRecorder
    {
    interface IAudioDevice;
        //interface IAudioRecorder;
        [default] interface IAudioRecorder;
        [default, source] dispinterface _IAudioRecorderEvents;
    };

//-----------------------------------------------------------------------

    [
        uuid(AB566C77-AF54-11DE-B5BE-00A0D15E9B20),
        helpstring("AudioDecoder Class")
    ]
    coclass AudioDecoder
    {
    interface IAudioDevice;
        interface IAudioRecorder;
        [default] interface IAudioDecoder;
        [default, source] dispinterface _IAudioDecoderEvents;
    };

/////////////////////////////////////////////////////////////////

The AudioDevice class simply implements the IAudioDevice interface (it
is not an ATL derived class).
The CRecorder class ha the following signature:

/////////////////////////////////////////////////////////////////

class ATL_NO_VTABLE CAudioRecorder :
    public CComObjectRootEx<CComSingleThreadModel>,
    public CComCoClass<CAudioRecorder, &CLSID_AudioRecorder>,
    public ISupportErrorInfo,
    public IConnectionPointContainerImpl<CAudioRecorder>,
    public CProxy_IAudioRecorderEvents<CAudioRecorder>,
    public AudioDevice,
    public IDispatchImpl<IAudioRecorder, &__uuidof(IAudioRecorder),
&LIBID_AxAudioLib4, /*wMajor =*/ 1, /*wMinor =*/ 0>
{
public:
    CAudioRecorder();

DECLARE_REGISTRY_RESOURCEID(IDR_AUDIORECORDER)

BEGIN_COM_MAP(CAudioRecorder)
    COM_INTERFACE_ENTRY(IAudioDevice)
    COM_INTERFACE_ENTRY(IAudioRecorder)
    COM_INTERFACE_ENTRY(IDispatch)
    COM_INTERFACE_ENTRY(ISupportErrorInfo)
    COM_INTERFACE_ENTRY(IConnectionPointContainer)
END_COM_MAP()

/////////////////////////////////////////////////////////////////

Now I have some difficult to define the CAudioDecoder class.
Since It has to implements IAudioDevice and IAudioRecorder I thought
to do something like this:

/////////////////////////////////////////////////////////////////
class ATL_NO_VTABLE CAudioDecoder :
  public CComObjectRootEx<CComSingleThreadModel>,
  public CComCoClass<CAudioDecoder, &CLSID_AudioDecoder>,
  public ISupportErrorInfo,
  public IConnectionPointContainerImpl<CAudioDecoder>,
  public CProxy_IAudioDecoderEvents<CAudioDecoder>,
  public AudioDevice,
  public CAudioRecorder,
  public IDispatchImpl<IAudioDecoder, &__uuidof(IAudioDecoder),
&LIBID_AxAudioLib4, /*wMajor =*/ 1, /*wMinor =*/ 0>
{
public:
  CAudioDecoder();

DECLARE_REGISTRY_RESOURCEID(IDR_AUDIODECODER)

BEGIN_COM_MAP(CAudioDecoder)
  COM_INTERFACE_ENTRY(IAudioDevice)
  COM_INTERFACE_ENTRY(IAudioRecorder)
  COM_INTERFACE_ENTRY(IAudioDecoder)
  COM_INTERFACE_ENTRY2(IDispatch, IAudioDecoder)
  COM_INTERFACE_ENTRY(ISupportErrorInfo)
  COM_INTERFACE_ENTRY(IConnectionPointContainer)
END_COM_MAP()
/////////////////////////////////////////////////////////////////

But it doesn't works.
Could someone give me some suggestion?

Thanks in advance,
Daniele.