[Discuss-gnuradio] question about gr-uhd c++ API

I developed a script for an UDH usrp_sink with GRC (in attachment).
Now, I would like to add it into my c++ application.

Someone has an example for that?
I don't find in the uhd c++ api how can I set input of my USRP with one or multiple signal source.

Thanks

Nicola B.