How to COM interfaces work

[StarGrazer via Digitalmars-d-learn]

On Sunday, 19 March 2017 at 03:10:02 UTC, Adam D. Ruppe wrote:
> On Sunday, 19 March 2017 at 02:04:53 UTC, StarGrazer wrote:
>> If I use it as a pointer in to the the D interface equivalent, 
>> it crashes as the value is not pointing to anything valid.
>
> What's the code look like? What interface too?

It's very complicated. I use a lot of reflection to extract the 
interface functions and build a d class from them.

Like I said, the initial dynamic COM interface works fine. I can 
call it's functions so all that code is irrelevant.

The problem is, some of those functions return COM 
interfaces(they inherit IDispatch interfaces in D).

The interfaces are generated from idl2d. So they are just 
standard d interfaces that only mock up the COM interfaces.

But it is probably not a D issue.

IDispatch.Invoke returns a COM VARIANT type with the return 
type(which is an IDispatch interface according to idl2d).



HRESULT CoCreateInstance(
   _In_  REFCLSID  rclsid,
   _In_  LPUNKNOWN pUnkOuter,
   _In_  DWORD     dwClsContext,
   _In_  REFIID    riid,
   _Out_ LPVOID    *ppv
);


https://msdn.microsoft.com/en-us/library/windows/desktop/ms686615(v=vs.85).aspx

I assume I'll have to use that to create the COM of COM by 
passing the returned value from invoke in to the pUnkOuter and do 
all that. I haven't tried it yet but will when I get a chance.


I'd just like to get some conformation on the process so at least 
I know I'm headed in the right direction. The project is pretty 
complex and most of the stuff is done in compile time code.