Hi!

I've been using the boost::python library for some time with few problems but now I got stuck.
Fortunately I isolated the problem.

In the class Domain below I defined a property called solver which returns a  shared_ptr<Solver>  instance:

namespace bp=boost::python;
class Solver
{
public:
    bool _b;
    void func() { _b = true; }
};
typedef shared_ptr<Solver> Solver_ptr;

class Domain
{
public:
    Solver_ptr solver;
    void set_solver(Solver_ptr s) { solver = s; }
};
typedef shared_ptr<Domain> Domain_ptr;

BOOST_PYTHON_MODULE(test) {
bp::class_<Solver, Solver_ptr>("Solver")
   .def("func", &Solver::func)
;
bp::class_<Domain, Domain_ptr>("Domain")
   .def("set_solver" , &Domain::set_solver)
   .add_property("solver" , &Domain::solver)
;
}


The code compiles ok. The problem appears while running in Python:

from test import *
d = Domain()
s = Solver()
d.set_solver(s)    # is it ok to do that?
d.solver.func()    # this line does not work

With the following error message:

Traceback (most recent call last):
  File "test_test.py", line 5, in <module>
    d.solver.func()
Boost.Python.ArgumentError: Python argument types in
    Solver.func(Solver)
did not match C++ signature:
    func(Solver {lvalue})

I suspect that the problem is related with add_property returning a shared_ptr<Solver> aka Solver_ptr.
It seems that add_property is returning a non lvalue Solver object.
I tried applying return value policies with no luck.
How can I get Domain::solver with type Solver_ptr in Python as a lvalue ?

Thanks!

Raul Durand