anchor.diff:    var hr = CoInitializeEx(
         nullptr, COINIT_APARTMENTTHREADED | COINIT_DISABLE_OLE1DDE);
     if (SUCCEEDED(hr)) {
  -    var pFileOpen = allocate<Uint64>();
  +    // Address of pointer variable that receives the interface pointer
  +    final pFileOpen = allocate<Uint64>();
   
       hr = CoCreateInstance(
           GUID.fromString(CLSID_FileOpenDialog).addressOf,
  
positive.code:         CLSCTX_ALL,
          GUID.fromString(IID_IFileOpenDialog).addressOf,
          pFileOpen);
      if (SUCCEEDED(hr)) {
        final pVt = Pointer<IFileDialogVtbl>.fromAddress(pFileOpen.value);
  
        print(printableAddress(pVt.ref.QueryInterface));
        print(printableAddress(pVt.ref.AddRef));
        print(printableAddress(pVt.ref.Show));
  
        final pFunc = pVt.ref.Show;
        final pFuncUint64 = Pointer<Uint64>.fromAddress(pFunc.address);
  
        final pFuncDart =
            Pointer<NativeFunction<IModalWindowShowNative>>.fromAddress(
                pFuncUint64.value);
        print(printableAddress(pFuncDart));
  
        MessageBox(NULL, TEXT('Preparing to invoke IFileDialog::Show'),
            TEXT('Preparing'), MB_OK);
        final pFuncCallable = pFuncDart.asFunction<IModalWindowShowDart>();
  
        pFuncCallable(pFileOpen, NULL);
        print('success');
      } else {
        COMError(hr, 'CoCreateInstance');
      }
  
negative.code:   Pointer<NativeFunction> SetFilter;
  }
  
  String pointerAsString(Pointer ptr) =>
      BigInt.from(ptr.address).toUnsigned(64).toRadixString(16).padLeft(16, '0');
  
  String uint64AsString(int addr) =>
      BigInt.from(addr).toUnsigned(64).toRadixString(16).padLeft(16, '0');
  
  void COMError(int hresult, String function) {
    hresult = hresult.toUnsigned(32);
  