Passing C++ class to DLL for callbacks from D (Steam)

[cc]

On Friday, 8 June 2018 at 02:52:10 UTC, Mike Parker wrote:
> On Friday, 8 June 2018 at 00:55:35 UTC, cc wrote:
>
>>
>> class CImpl : CCallbackBase {
>> 	extern(C++) {
>
>> If anyone has any insight to provide it would be greatly 
>> appreciated, thanks!
>
> I've not used any of the C++ interfacing features yet, but my 
> understanding is the extern(C++) has to apply to the class 
> declaration itself, not only the member functions:
>
> extern(C++)
> class CImpl : CCallbackBase {
>
> Does that make a difference?

Tried wrapping the CImpl class in extern(C++), no luck.. tried 
final keyword on the methods too.  Thanks though.