[C++-sig] ownership of C++ object extended in Python

[Tiago Coutinho]

Hello all,

I want to export a class 'A' from an external library to python.
In python I need to extend the class and I need to tell the library that it
will 'own' the object.

I have tried the example in:

http://wiki.python.org/moin/boost.python/HowTo

(chapter "ownership of C++ object")

And executing the code I send in attachment I get:

$ python test1.py

Traceback (most recent call last):
  File "test1.py", line 19, in <module>
    main()
  File "test1.py", line 15, in main
    print(a.get_int())
Boost.Python.ArgumentError: Python argument types in
    A.get_int(B)
did not match C++ signature:
    get_int(A {lvalue})

Can you tell me what I am missing in the code?

Thank you in advance

PS: Sorry quality of the Makefile.

Regards
Tiago

Makefile
Description: Binary data

// c++ -o test1 test1.cpp -lboost_python -I/usr/include/python2.7 -lpython2.7

#include <memory>
#include <boost/python.hpp>

using namespace std;
using namespace boost::python;

class A
{
public:
    A() {}
    virtual ~A() {}
    
    int get_int() { return 22; }
};

class AWrap: public A
{
public:

    PyObject *self;

    AWrap(PyObject* self_): self(self_) { Py_INCREF(self); }
    ~AWrap() { Py_DECREF(self); }
};

class Owner
{
public:
    A* a;
    Owner(): a(0) {}
    virtual ~Owner() { if (a!=0) delete a;}
    
    void set_A(A* a_) { a=a_; }
};

void set_A(Owner& self, auto_ptr<A> a_)
{
    self.set_A(a_.get());
    a_.release();
}

BOOST_PYTHON_MODULE(_test1)
{
    class_<A, auto_ptr<AWrap>, boost::noncopyable >("A")
        .def("get_int", &A::get_int)
    ;
   
    implicitly_convertible<auto_ptr<AWrap>, auto_ptr<A> >();
    
    class_<Owner>("Owner")
        .def("set_A", &set_A)
    ;
}

test1.py
Description: Binary data

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