BUG: MIDL Gives Warning MIDL2039 When Decimal Used as Parameter Type in IDL

• Microsoft Visual C++, 32-bit Editions, versions 5.0, 6.0

SYMPTOMS

When you compile an .idl file with decimal as the type of parameter for a method, you get an MIDL2039 warning. But it is documented that the decimal is a valid type for a parameter (for example, search the MSDN Library Index for "oleautomation").

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 the Behavior

1. Copy the following code into a new file and save it as an .idl file.




import "oaidl.idl";
import "ocidl.idl";
[
	object,
	uuid(DE4C1D8D-C007-11D2-B978-00AA00C0018D),
	dual,
	helpstring("IFoo1 Interface"),
	pointer_default(unique)
]
interface IFoo1 : IDispatch
{
};

[
	uuid(DE4C1D80-C007-11D2-B978-00AA00C0018D),
	version(1.0),
	helpstring("huh 1.0 Type Library")
]
library HUHLib
{
	importlib("stdole2.tlb");

	[
		uuid(DE4C1D8F-C007-11D2-B978-00AA00C0018D),
		hidden,
		helpstring("_IFoo1Events Interface")
	]
	dispinterface _IFoo1Events
	{
		properties:
		methods:
		[id(1), helpstring("method MIDL2039")] HRESULT MIDL2039([in] Decimal d);
	};

	[
		uuid(DE4C1D8E-C007-11D2-B978-00AA00C0018D),
		helpstring("Foo1 Class")
	]
	coclass Foo1 {

		[default] interface IFoo1;
		[default, source] dispinterface _IFoo1Events;
	};
}; 

2. Now compile it with Microsoft Interface Definition Language (MIDL) and see the warning:

   
   huh.idl(38) : warning MIDL2039 : interface does not conform to 
   [oleautomation] attribute :   [ Parameter 'd' of Procedure 'MIDL2039' ( 
   Dispinterface '_IFoo1Events' ) ] 

Additional query words:

Keywords : kbCompiler kbCOMt kbVC500bug kbVC600bug
Version : winnt:5.0,6.0
Platform : winnt
Issue type : kbbug