Interfacing with C++

[Mike Parker]

On Sunday, 4 February 2018 at 08:17:31 UTC, Mike Parker wrote:

>
> So assuming CV_CDECL is cdecl, this should do it:
>
> extern(C) alias CvCmpFunc = int function(const(void)*, 
> const(void)*, void*);

Assuming this is OpenCV, Looking at [1], it's cdecl only on 
Windows. Empty everywhere else. So since OpenCV is a C++ library 
these days, I guess it needs to be declared like this:

version(Windows)
     extern(C) alias CvCmpFunc = int function(const(void)*, 
const(void)*, void*);
else
     extern(C++) alias CvCmpFunc = int function(const(void)*, 
const(void)*, void*);

Though, I'm curious why anyone would want to declare a callback 
in a C++ program as cdecl only on Windows and use the default C++ 
convention everywhere else. I suggest you dig into it and make 
sure that's what's intended. And good luck binding to OpenCV!


[1] 
https://github.com/opencv/opencv/blob/master/modules/core/include/opencv2/core/types_c.h#L68