[Discuss-gnuradio] Extending UHD USRP Sink in out-of-tree module

[Sean Nowlan]

I want to add some functionality to gr_uhd_usrp_sink to change frontend 
gain and tune the DDC. I've achieved part of this in the past by 
modifying the files directly in gnuradio/gr-uhd, but that's an imprecise 
way to do it. Would you recommend I:

1) copy the code from the gnuradio tree to my out-of-tree module, change 
namespaces, etc. and add my functionality?
2) create my own private uhd_usrp_sink_impl that extends gnuradio's 
uhd_usrp_sink and add my functionality there?
3) something else?

I remember reading something on this list from somebody who rolled their 
own usrp wrapper. Any hints?

Thanks,

Sean