BUG: MIDL2039 Warning with IFontDisp/IPictureDisp Parameter Type

ID: Q196830

The information in this article applies to:

The Microsoft Active Template Library (ATL), versions 2.1, 3.0, used with:
- Microsoft Visual C++, 32-bit Editions, versions 5.0, 6.0

SYMPTOMS

When you compile an .idl file with IFontDisp or IPictureDisp as parameters of methods in Visual C++ 5.0 or Visual C++ 6.0, you get a MIDL2039 warning.

CAUSE

This is due to a bug in Ocidl.idl source. You must add the dual attribute to the interface declarations for IFontDisp and IPictureDisp.

RESOLUTION

To prevent the warning, add the dual attribute to the IFontDisp and IPictureDisp interface declarations in Ocidl.idl, as in the following example:


   [
      object,
      dual,
      uuid(BEF6E003-A874-101A-8BBA-00AA00300CAB),
      pointer_default(unique)
   ]

   interface IFontDisp : IDispatch
   {
      typedef IFontDisp * LPFONTDISP;
   }

   [
      object,
      dual,
      uuid(7BF80981-BF32-101A-8BBB-00AA00300CAB),
      pointer_default(unique)
   ]

   interface IPictureDisp : IDispatch
   {
      typedef IPictureDisp * LPPICTUREDISP;
   }

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

Steps to Reproduce Behavior

Create a new ATL COM AppWizard Project with DLL as the Server Type.

Insert a new ATL Control using the ATL Object Wizard, and add the Font stock property by selecting it from the Stock Properties tab of the wizard.

Build the .idl file generated by the wizard.

You should receive the following warnings:

warning MIDL2039 : interface does not conform to [oleautomation]
attribute

Additional query words:

Keywords : kbcode kberrmsg kbActiveX kbATL210bug kbAutomation kbVC500bug kbVC600bug kbATL300bug kbGrpMFCATL kbIDL
Version : WINDOWS:2.1,3.0
Platform : WINDOWS
Issue type : kbbug