[Boost-users] [Python] Wrapping a base class' method

From: bernhard.maeder_at_[hidden]
Date: 2006-11-17 10:11:13

Hi Boosters

I'm trying to export some base class' methods  with the derived class
directly. See the following code:

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

struct my_base_class
{
    int const & get_base_i() const
    {
        return i_;
    }
    int i_;
};

struct my_class
  : my_base_class
{
    int const & get_i() const
    {
        return i_;
    }

    int i_;
};

using namespace boost::python;

BOOST_PYTHON_MODULE(_test)
{
    class_<my_class>("MyClass")
      .add_property("i",        make_function(&my_class::get_i,
return_value_policy<copy_const_reference>()))
      .add_property("basei",    make_function(&my_class::get_base_i,
return_value_policy<copy_const_reference>()))
      ;
}

// -----------------------------------------------------

Now python throws the following at me:

h[ 1] >>> from _test import *
h[ 1] >>> MyClass().basei
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
Boost.Python.ArgumentError: Python argument types in
    None.None(MyClass)
did not match C++ signature:
    None(my_base_class {lvalue})

So, my question is: Am I not supposed to do this at all? The same seems to
work flawlessly when returning by value instead of by reference....

Thanks for your input

Bernhard
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