IntPtr vs. As Any in COM

Question

i'm developing a COM object that should work in C# and also in VBScript. Also it must support 32 and 64 bits.

The problem I have is with pointers. See part of my .IDL

HRESULT Copy([in] PTRTYPE destAddr, [in] PTRTYPE srcAddr, [in] int bytes); 

If I declare PTRTYPE as void*, c# sees them as an IntPtr and VB6/VBScript sees them "As Any"

The problem with this approach is that I cannot do simpler pointer math with "Any" type parameters.

If I declare PTRTYPE as long (and "hyper" in 64 bits), now I can do pointer math but in C# I have two different definitions for the same method depending 32/64 bit platform.

I wish to avoid using VARIANT as PTRTYPE type.

Is there any way to make it compatible with both C# and VBScript?

Thanks in advance, Mauro.

Answer 1

The solution I adopted was the following:

1) Copy .idl to another folder

2) Replace the __int3264 with void* in the variables you want to be IntPtr

3) Build the .tlb file from the .idl one

4) Build a primary interop based on the .tlb file.

Voilá!

Regards, Mauro.

Answer 2

I would recommend not forcing the consumer of your type to do the pointer math.

If declare this as void, you can always allow the offsets to be passed as a parameter, instead of forcing the consumer to do the manipulation. This could look a bit more like this Array.Copy overload in the .NET framework, where the source + destination have an offset passed as a simple integer.

By doing this, you allow the method to work correctly no matter what consumer you choose, as well as providing you a means of doing the validation (ie: making sure the offset is legitimate) in your own code instead of relying on the consumer.