On Friday, 4 May 2018 at 07:49:02 UTC, Robert M. Münch wrote:
I have a static C++ and can't make it to get a correct binding for one function:

DMD: public: unsigned int __cdecl b2d::Context2D::_begin(class b2d::Image & __ptr64,class b2d::Context2D::InitParams const * __ptr64 const) __ptr64 LIB: public: unsigned int __cdecl b2d::Context2D::_begin(class b2d::Image & __ptr64,class b2d::Context2D::InitParams const * __ptr64) __ptr64

So I somehow get some more const from D. This is the code I used:

final uint _begin(ref Image image, const(InitParams) initParams);

Which creates a const pointer to a const class signature. But it should only be a const pointer. Any idea how to solve this?

The problem is that const in D is transitive. That means T * const from C++ is not expressible in D. Any reference through a const becomes const. To use it, IMO your best bet is to make a wrapper function on the C++ side like this:

unsigned int __cdecl b2d::Context2D::_begin(class b2d::Image & im,class b2d::Context2D::InitParams const * const InitParams)
{
    return //the call to the original c++ function
}

Alternatively you can use dpp, or dstep or some similar tool to try and let the tool create bindings. As a last ditch, you can force the mangle to match by using pragma(mangle, ...) like this:

pragma(mangle, _ZactualMangleFromC++Compiler)
final uint _begin(ref Image image, const(InitParams) initParams);

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