A question about C++ interop

[YD]

On Sunday, 29 March 2020 at 15:20:52 UTC, YD wrote:
> On Sunday, 29 March 2020 at 01:50:24 UTC, evilrat wrote:
>> [...]
>
> Thanks, dummy placeholder works. But there is a new problem on 
> Windows, let's say there are two classes in C++:
>
> [...]

Actually I found that if I create a C wrapper like

     extern "C" void X_call(X const *, Y const *);

then it will work. So I have a workaround now. However, out of 
curiosity, is there a way to do this directly without C wrapper? 
Thanks.