[C++-sig] Need help with inheritance problem

[Simon Pickles]

Hi,

I am trying to expose part of the bullet dynamics library to my python code.
I simply need to expose a few accessors of a type btVector3. This 
inherits from a class which is itself derived. I seem to be struggling 
to get this right.

Here is my attempt:

BOOST_PYTHON_MODULE(HybridZone)
{
   using namespace boost::python;

   class_<btQuadWordStorage>("btQuadWordStorage")
       ;
      
   // I am trying to expose getX()
   class_<btQuadWord, bases<btQuadWordStorage> >("btQuadWord")
       .def("getX", &btQuadWord::getX, return_internal_reference<1, 
with_custodian_and_ward<1, 2> >());
       //.add_property("x", &btQuadWord::x) // doesn't compile either
       ;
      
   class_<btVector3, bases<btQuadWord> >("btVector3", init<float, 
float, float>())
       ;
}

You can see my structure is an attempt to mimic the inheritance diagram 
found here

http://www.continuousphysics.com/Bullet/BulletFull/classbtVector3.html

I am trying to expose btVector3::getX(), inherited from btQuadWord

Thanks for your time and advice.

Simon

ps: heres the error message, on gcc4.2.4, Ubuntu 8.04:

...updating 3 targets...
gcc.compile.c++ bin/gcc-4.2.4/debug/HybridZone.o
/home/simon/Source/boost_1_37_0/boost/python/object/make_instance.hpp: 
In static member function \u2018static PyObject* 
boost::python::objects::make_instance_impl<T, Holder, 
Derived>::execute(Arg&) [with Arg = float*, T = float, Holder = 
boost::python::objects::pointer_holder<float*, float>, Derived = 
boost::python::objects::make_ptr_instance<float, 
boost::python::objects::pointer_holder<float*, float> >]\u2019:
/home/simon/Source/boost_1_37_0/boost/python/to_python_indirect.hpp:106:   
instantiated from \u2018static PyObject* 
boost::python::detail::make_reference_holder::execute(T*) [with T = 
float]\u2019
/home/simon/Source/boost_1_37_0/boost/python/to_python_indirect.hpp:70:   
instantiated from \u2018PyObject* boost::python::to_python_indirect<T, 
MakeHolder>::execute(const U&, mpl_::false_) const [with U = float, T = 
const float&, MakeHolder = 
boost::python::detail::make_reference_holder]\u2019
/home/simon/Source/boost_1_37_0/boost/python/to_python_indirect.hpp:41:   
instantiated from \u2018PyObject* boost::python::to_python_indirect<T, 
MakeHolder>::operator()(const U&) const [with U = float, T = const 
float&, MakeHolder = boost::python::detail::make_reference_holder]\u2019
/home/simon/Source/boost_1_37_0/boost/python/detail/invoke.hpp:88:   
instantiated from \u2018PyObject* 
boost::python::detail::invoke(boost::python::detail::invoke_tag_<false, 
true>, const RC&, F&, TC&) [with RC = 
boost::python::to_python_indirect<const float&, 
boost::python::detail::make_reference_holder>, F = const btScalar& 
(btQuadWord::*)()const, TC = 
boost::python::arg_from_python<btQuadWord&>]\u2019
/home/simon/Source/boost_1_37_0/boost/python/detail/caller.hpp:223:   
instantiated from \u2018PyObject* 
boost::python::detail::caller_arity<1u>::impl<F, Policies, 
Sig>::operator()(PyObject*, PyObject*) [with F = const btScalar& 
(btQuadWord::*)()const, Policies = 
boost::python::return_internal_reference<1u, 
boost::python::with_custodian_and_ward<1u, 2u, 
boost::python::default_call_policies> >, Sig = boost::mpl::vector2<const 
btScalar&, btQuadWord&>]\u2019
/home/simon/Source/boost_1_37_0/boost/python/object/py_function.hpp:38:   
instantiated from \u2018PyObject* 
boost::python::objects::caller_py_function_impl<Caller>::operator()(PyObject*, 
PyObject*) [with Caller = boost::python::detail::caller<const btScalar& 
(btQuadWord::*)()const, boost::python::return_internal_reference<1u, 
boost::python::with_custodian_and_ward<1u, 2u, 
boost::python::default_call_policies> >, boost::mpl::vector2<const 
btScalar&, btQuadWord&> >]\u2019
HybridZone.cpp:88:   instantiated from here
/home/simon/Source/boost_1_37_0/boost/python/object/make_instance.hpp:24: 
error: invalid application of \u2018sizeof\u2019 to incomplete type 
\u2018boost::STATIC_ASSERTION_FAILURE<false>\u2019

   "g++"  -ftemplate-depth-128 -O0 -fno-inline -Wall -g -fPIC  
-DBOOST_DATE_TIME_DYN_LINK=1 -DDATE_TIME_INLINE  
-I"/home/simon/Source/boost_1_37_0" 
-I"/home/simon/Source/bullet-2.72/src" -I"/usr/local/include/python2.5" 
-c -o "bin/gcc-4.2.4/debug/HybridZone.o" "HybridZone.cpp"

...failed gcc.compile.c++ bin/gcc-4.2.4/debug/HybridZone.o...
...skipped <pbin/gcc-4.2.4/debug>HybridZone.so for lack of 
<pbin/gcc-4.2.4/debug>HybridZone.o...
...skipped <p.>HybridZone.so for lack of 
<pbin/gcc-4.2.4/debug>HybridZone.so...
...failed updating 1 target...
...skipped 2 targets...

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