15.03.2020 22:39, Ferhat Kurtulmuş пишет:
The original C++ class
https://github.com/opencv/opencv/blob/master/modules/core/include/opencv2/core/types.hpp#L315:
template<typename _Tp> class Size_
{
public:
typedef _Tp value_type;
//! default constructor
Size_();
Size_(_Tp _width, _Tp _height);
Size_(const Size_& sz);
Size_(Size_&& sz) CV_NOEXCEPT;
Size_(const Point_<_Tp>& pt);
Size_& operator = (const Size_& sz);
Size_& operator = (Size_&& sz) CV_NOEXCEPT;
//! the area (width*height)
_Tp area() const;
//! aspect ratio (width/height)
double aspectRatio() const;
//! true if empty
bool empty() const;
//! conversion of another data type.
template<typename _Tp2> operator Size_<_Tp2>() const;
_Tp width; //!< the width
_Tp height; //!< the height
};
// my auxiliary cpp code:
cv::Size_<int>* createSizeIntWH(int _width, int _height){
return new cv::Size_<int>(_width, _height);
}
void deleteSizeInt(cv::Size_<int> *&sz){
delete sz;
}
// d code:
extern(C++, cv){
class Size_(_Tp){
@disable this();
final _Tp area() const;
final double aspectRatio() const;
final bool empty() const;
_Tp width; //!< the width
_Tp height; //!< the height
}
}
// my test code that fails:
Size_!int sz = createSizeIntWH(200, 100);
writeln(sz.width);
What is the D version of `createSizeIntWH`? In C++ it returns a pointer
but in D version it returns an instance.
One of the problems is that sz.width is not printed as 200, but a random
int.
Other problem is that if I try to call one of area, aspectRatio, and
empty, it does not compile yielding a linker error:
error LNK2019: unresolved external symbol "public: int __cdecl
cv::Size_<int>::area(void)const " (?area@?$Size_@H@cv@@QEBAHXZ)
referenced in function _Dmain
Somehow linker cannot locate that symbol. Is this a name mangling issue?
In the same library I could successfully interface cv::Mat which is a
template-free definition. I suspect if D allows interfacing C++ class
templates since docs do not cover this, but only struct templates?
