Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 14:52:21 UTC, kinke wrote: Trivial cases like yours should actually work wrt. using C++ ctor implementations from D IIRC. Ah, you need at least one virtual function in the C++ class (because D always reserves a vptr, the pointer to the class vtable).
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 08:15:20 UTC, Luhrel wrote: But somehow I got a segfault on dcpp.getNumber(true). That's because you declare it as virtual in D (default for classes, use `final`), but non-virtual in C++. You also forgot to add the class field to the D declaration (yes, D needs to know about the struct layout and size too, especially when you `new` the class in D and let the GC allocate it). Trivial cases like yours should actually work wrt. using C++ ctor implementations from D IIRC.
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 10:21:54 UTC, norm wrote: On Saturday, 1 February 2020 at 08:38:22 UTC, Luhrel wrote: On Saturday, 1 February 2020 at 08:32:51 UTC, Ferhat Kurtulmuş wrote: On Saturday, 1 February 2020 at 08:27:07 UTC, Luhrel wrote: On Saturday, 1 February 2020 at 08:21:29 UTC, Ferhat Kurtulmuş wrote: [...] Oh I see, so there's definitively no way to call a c++ ctor without modifying the c++ code ? İf you are not allowed to modify that c++ code, you can write a createInstance function in your custom cpp file. That was my fear. It isn't too bad, you need a simple wedge written in C++ that returns an instance of any T you want. A simple template function usually works, or to make it more generic you can use a variadic template to handle N args, but I find variadic templates in C++ are still annoying to use. And do not forget to write a void cppDestroy(T instance) function that runs delete instance in c++ so that you can call it from D code. void cppDestroy(T instance)
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 08:38:22 UTC, Luhrel wrote: On Saturday, 1 February 2020 at 08:32:51 UTC, Ferhat Kurtulmuş wrote: On Saturday, 1 February 2020 at 08:27:07 UTC, Luhrel wrote: On Saturday, 1 February 2020 at 08:21:29 UTC, Ferhat Kurtulmuş wrote: You cannot. https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d You must use a factory method like createInstance. Oh I see, so there's definitively no way to call a c++ ctor without modifying the c++ code ? İf you are not allowed to modify that c++ code, you can write a createInstance function in your custom cpp file. That was my fear. It isn't too bad, you need a simple wedge written in C++ that returns an instance of any T you want. A simple template function usually works, or to make it more generic you can use a variadic template to handle N args, but I find variadic templates in C++ are still annoying to use.
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 08:32:51 UTC, Ferhat Kurtulmuş wrote: On Saturday, 1 February 2020 at 08:27:07 UTC, Luhrel wrote: On Saturday, 1 February 2020 at 08:21:29 UTC, Ferhat Kurtulmuş wrote: You cannot. https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d You must use a factory method like createInstance. Oh I see, so there's definitively no way to call a c++ ctor without modifying the c++ code ? İf you are not allowed to modify that c++ code, you can write a createInstance function in your custom cpp file. That was my fear.
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 08:27:07 UTC, Luhrel wrote: On Saturday, 1 February 2020 at 08:21:29 UTC, Ferhat Kurtulmuş wrote: You cannot. https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d You must use a factory method like createInstance. Oh I see, so there's definitively no way to call a c++ ctor without modifying the c++ code ? İf you are not allowed to modify that c++ code, you can write a createInstance function in your custom cpp file.
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 08:21:29 UTC, Ferhat Kurtulmuş wrote: You cannot. https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d You must use a factory method like createInstance. Oh I see, so there's definitively no way to call a c++ ctor without modifying the c++ code ?
Re: How to call a extern C++ class constructor ?
On Saturday, 1 February 2020 at 08:15:20 UTC, Luhrel wrote: Hello there, I would like to know how can I call a C++ ctor. [...] You cannot. https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d You must use a factory method like createInstance.
How to call a extern C++ class constructor ?
Hello there,
I would like to know how can I call a C++ ctor.
Actually, I have this:
C++:
CppClass.cpp
#include "CppClass.h"
AmazingCppClass::AmazingCppClass()
{
number = 124;
}
int AmazingCppClass::getNumber(bool show)
{
if (show)
printf("Number: %s", number);
return number;
}
void AmazingCppClass::add(int num)
{
number += num;
}
CppClass.h:
#include
class AmazingCppClass
{
private:
int number;
public:
AmazingCppClass();
int getNumber(bool show);
void add(int num);
};
D:
app.d
import std.stdio;
void main()
{
auto dcpp = new AmazingCppClass();
dcpp.getNumber(true); //segfault here
}
extern(C++) class AmazingCppClass
{
this();
int getNumber(bool show);
void add(int num);
}
But somehow I got a segfault on dcpp.getNumber(true).
I found that there's a __cpp_new
(https://dlang.org/phobos/core_stdcpp_new_.html), but I have no
idea how to use it and the doc doesn't say a lot about this
(https://dlang.org/spec/cpp_interface.html#using_cpp_classes_from_d)
Do you guys know ?
