hi, im trying to interface a cpp class. I'd like to interface a bigger library and I'm trying to figure out the minimum effort.

--- c++ part:
#include <iostream>
class some_class {
public:
  static some_class* __ctor();
  some_class();
  ~some_class();
  void some_method();
};
some_class* some_class::__ctor() {
  auto thiz = new some_class();
  std::cout << "hello from __ctor, thiz:" << thiz << std::endl;
  return thiz;
}
some_class::some_class() { std::cout << "some_class constructor, this:" << this << std::endl; }
some_class::~some_class() { std::cout << "some_class destructor, this:" << this << std::endl; }
void some_class::some_method() {
  std::cout << "some_class some_method, this:" << this << std::endl;
}

--- d part:
extern (C++) {
  class some_class {
    final this();
    final ~this();
    final void some_method();
  }
}
void main() {
  some_class someClass = new some_class(); // works, __ctor() gets called, and it calls the constructor.
  someClass.some_method; // works
  destroy(someClass); // crashes (SIGSEGV) inside lifetime.d rt_finalize2()
}

---
OS: ubuntu 17.10
compiler: DMD64 D Compiler v2.077.0

I could do the instancing/destruction by functions and write a custom d class that calls these methods in this()/~this(). But I was hoping not needing to write a class in D AND in cpp. and i was hoping to save another step/level of instancing.

Any idea how to make the destructor of cpp compatible with "~this()"?

Thx in advance
Markus

On Tuesday, 21 November 2017 at 23:12:33 UTC, Markus wrote:
> hi, im trying to interface a cpp class. I'd like to interface a bigger library and I'm trying to figure out the minimum effort.

Possibly it will be interesting https://www.youtube.com/watch?v=HTgJaRRfLPk

On Wednesday, 22 November 2017 at 08:29:26 UTC, MGW wrote:
> Possibly it will be interesting

https://pp.userapi.com/c639524/v639524332/60240/uH3jnxrchik.jpg

22.11.2017 02:12, Markus пишет:

snip

> I could do the instancing/destruction by functions and write a custom d class that calls these methods in this()/~this(). 
This is what I used to do as special members like ctor/dtor did not supported in D before, but your example of using ctor is interesting.
What about dtor - you allocate class using D GC but try to destroy it manually - namely this I guess gives you an error in rt_finalize2 because it tries to destroy object that has been destroyed.

On Wednesday, 22 November 2017 at 08:43:54 UTC, drug wrote:
> 22.11.2017 02:12, Markus пишет:
> What about dtor - you allocate class using D GC but try to destroy it manually - namely this I guess gives you an error in rt_finalize2 because it tries to destroy object that has been destroyed.
hmm... I'm not sure. I compiled dmd and it's druntime in debug and I'm stepping through it. Seems there has to be a "ClassInfo" filled with data. In my case it's filled with garbage. So the call ClassInfo.destructor fails, because destructor is an invalid pointer. The GC.collect works, but doesn't call the destructor.
https://github.com/dlang/druntime/blob/3d8d4a45c01832fb657c16a656b6e1566d77fb21/src/rt/lifetime.d#L1391
I know constructors and destructors are not supported. And I get that point for move/copy... constructors. But I don't get it for simple construction and destruction.

Markus

another indicator (as documented) that GC destructor won't work
// extern(C++) classes don't have a classinfo pointer in their vtable so the GC can't finalize them
https://github.com/dlang/druntime/blob/3d8d4a45c01832fb657c16a656b6e1566d77fb21/src/rt/lifetime.d#L90
annoying :(

Markus

22.11.2017 19:06, Markus пишет:
> another indicator (as documented) that GC destructor won't work
> // extern(C++) classes don't have a classinfo pointer in their vtable so the GC can't finalize them
> https://github.com/dlang/druntime/blob/3d8d4a45c01832fb657c16a656b6e1566d77fb21/src/rt/lifetime.d#L90 
> 
> annoying :(
> 
> Markus
I've made a guess that more c++ support were added in the last frontend version, well I was wrong