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reply Markus <contact markus-lanner.com> writes:
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
Nov 21 2017
next sibling parent reply MGW <mgw yandex.ru> writes:
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
Nov 22 2017
parent MGW <mgw yandex.ru> writes:
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
Nov 22 2017
prev sibling parent reply drug <drug2004 bk.ru> writes:
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.
Nov 22 2017
parent reply Markus <contact markus-lanner.com> writes:
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
Nov 22 2017
parent reply Markus <contact markus-lanner.com> writes:
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
Nov 22 2017
parent drug <drug2004 bk.ru> writes:
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/s
c/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
Nov 22 2017