Accessing COM Objects

[Mike Parker via Digitalmars-d-learn]

On Monday, 13 June 2016 at 04:52:49 UTC, Mike Parker wrote:
> On Monday, 13 June 2016 at 02:08:22 UTC, Incognito wrote:
>
>> What interface are you talking about? How can I cast to 
>> something I don't have? I do not have a photoshop COM 
>> interface. Are you saying that if CoCreateInstance worked that 
>> I can then use the iid or pUnk to access the COM? Do I get the 
>> members by trial and error? pUnk.width? Even if 
>> CoCreateInstance passed, what do I do next?
>
> You have to define the interface yourself, extending from 
> IUnknown, implementing whatever functions are available on the 
> COM interface you want. Here's an example for the ID3D11Device 
> interface:
>
> https://github.com/auroragraphics/directx/blob/master/d3d11.d#L1332

Sorry. Hit send too soon.

Once you've got your interface defined, you should be able to do 
this:

MyCOMType mct;
auto hr = CoCreateInstance(&CLSID_DOMDocument60, null, 
CLSCTX_ALL, &iid, &cast(void*)mct);

It's been a long time since I worked directly with COM, so there 
are probably details I'm missing, but this is the general idea.