[Boost-users] Boost Python: Howto wrap "out" arguments of a methode

How to wrap methode Get with Boost.Python? class MyClass { public: MyClass(); void GetX(double &pos_x); [...] I'v tried it with: .def( "GetX" , &::MyClass::GetX , bp::arg("") , bp::return_value_policy() >() But when I try it in python: Boost.Python.ArgumentError: Python argument types in MyClass.GetX(MyClass, int) did not match C++ signature: GetX(class MyClass::LedPosition_C {lvalue}, int {lvalue} ) Any ideas? Thanks Alexander