On Friday, 4 May 2018 at 07:57:26 UTC, Uknown wrote:
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);
Using pragma(mangle) isn't really a solution though, unless you
only plan on using one platform/compiler. C++ doesn't have a
single standard name mangling. You would need to get the name
mangling for every compiler you plan to use then use a version
define fore each. Which isn't really practical for how many
bindings you would need to do that for.
The easiest solution is to just write C bindings for the C++
library then use those instead from D.
