Yes, that is the problem - not sure why modtool bind is not doing the trick. You can manually add the method if you want, which would just look like:
.def(py::init(&adding_ff::make),
py::arg("constant0"),
D(adding_ff,make)
)
.def("set_constant0", &adding_ff::set_constant0)
;
The only thing then to be careful of is if you run modtool bind again, it would blow away your changes
It may be worth trying to figure out why modtool bind is not doing the full set of methods that pygccxml would find, such as trying a new oot from scratch and see if the same problem exists, now that pygccxml is installed