Re: Overloaded make() with pybind11

[Josh]

Hi Daniel,

Unfortunately, the automated tools aren't smart enough to come up with the bindings for the overload make function.  It doesn't seem to be a bad design decision in and of itself, and fortunately, it is done in certain places in the GR code.

Take a look at gr-uhd/python/uhd/bindings/usrp_sink_python.cc

        .def(py::init((std::shared_ptr<gr::uhd::usrp_sink>(*)(const ::uhd::device_addr_t&,
                                                              const ::uhd::stream_args_t&,
                                                              const std::string&)) &
                      usrp_sink::make),
             py::arg("device_addr"),
             py::arg("stream_args"),
             py::arg("tsb_tag_name") = "",
             D(usrp_sink, make))

        .def(py::init((std::shared_ptr<gr::uhd::usrp_sink>(*)(const std::string&,
                                                              const ::uhd::stream_args_t&,
                                                              const std::string&)) &
                      usrp_sink::make),
             py::arg("device_addr"),
             py::arg("stream_args"),
             py::arg("tsb_tag_name") = "",
             D(usrp_sink, make))

When init is overloaded in the python bindings, the make functions have to be given explicit function pointers.  So you will have to do this manually.

Josh

On Fri, Jan 22, 2021 at 1:12 PM Daniel Estévez <daniel@destevez.net> wrote:

Hi,

I'm porting gr-satellites to GNU Radio 3.9. I have some blocks that have
an overloaded make() method, for example:

https://github.com/daniestevez/gr-satellites/blob/master/include/satellites/decode_rs.h

Maybe this wasn't a very wise design decision on my side.

Now I'm wondering if it's possible to use this with pybind11, and if so
how to do it.

gr_modtool bind (with pygccxml installed) is generating this:

https://gist.github.com/daniestevez/a3d0aaf7e6b2a68933ebb30e9043e7ac

which gives build problems like

/home/daniel/gr-satellites/python/bindings/decode_rs_python.cc: In
function 'void bind_decode_rs(pybind11::module&)':
/home/daniel/gr-satellites/python/bindings/decode_rs_python.cc:39:39:
error: no matching function for call to 'init(<unresolved overloaded
function type>)'
    39 |         .def(py::init(&decode_rs::make),
       |                                       ^


Best,

Daniel.