Is it ok to do the following ?
I.e. derive a D-class from a CPP-class.
The compiler did not complained, and it was OK for him.

c++ -c MyClass.cpp
ldc2 main.d MyClass.o -L-lstdc++

extern(C++){
	class MyClass {
		public:
			int num=1;
			void myMethod();
	};
};

class Derived : MyClass{
};

int main(){
	Derived myObj;
	myObj.myMethod();
	return 0;
}

Could I use this method for using the C++-WXWIDGETS library directly?

PS: I managed to link to phobo's/runtime & wxgtk at the same time.
It goes like this [So someone does not need to re-invent the weel]

ldc2 - c test.d
c++ test.o -o test -L/usr/local/lib -lphobos2-ldc -ldruntime-ldc -Wl,--gc-sections -lexecinfo -lpthread -lm -m64 `wxgtk3u-3.0-config --cxxflags --libs`

Following code produces a linker error.
d: error: undefined symbol: wxApp::OnInit()

extern(C++)
	{class wxApp {
			public:
			bool OnInit();
			//virtual bool Oninit();
		}
	}

class MYAPP: wxApp {
			alias OnInit=wxApp.OnInit;
			bool OnInit(){return true;};
}

int main(){
	return 0;
}

It is rather clear what I want to achieve but virtual functions give me headache because dlang does not now the word virtual.

On Wednesday, 28 April 2021 at 19:46:00 UTC, Alain De Vos wrote:

extern(C++)
	{class wxApp {
			public:
			bool OnInit();
			//virtual bool Oninit();

you mean abstract for that one?

  	alias OnInit=wxApp.OnInit;

idk what you intend to do with this, this pattern is for merging overloads not overriding

  	bool OnInit(){return true;};

and you might want override there

On Wednesday, 28 April 2021 at 19:46:00 UTC, Alain De Vos wrote:

It's virtual by default. The opposite is final.

On Thursday, 29 April 2021 at 06:38:53 UTC, evilrat wrote:

by default, excepted if protection is private or package.