# Re: Suppressing UHD prints **URL:** \ **Category:** GNU Radio\ **Created:** [July 6, 2015, 7:26pm UTC](https://www.ruby-forum.com/t/re-suppressing-uhd-prints/242606 "2015-07-06T19:26:28Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![musicdenotation](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@musicdenotation](https://www.ruby-forum.com/u/musicdenotation)\ **Post date:** [July 6, 2015, 7:26pm UTC](https://www.ruby-forum.com/t/re-suppressing-uhd-prints/242606/1 "2015-07-06T19:26:28Z")
@Sebastion “Even if ’ uhd::msg::register\_handler’ would be exposed to python, you still can’t drop-in your own null-handler. Swig doesn’t support callbacks in the target language (python).” This seems precisely what I have observed working with my example from my question on 7/2/2015 “message passing: strobe or \_post?” I use a Python method as a callback given to .set\_msg\_handler. This is certainly called when I use the message strobe to input a message to the block, but not when using \_post. Is this some new feature? Or am I wrong that the operation is the same? Jared. ---
**Author:** ![jared](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/848f3c/32.png) [@jared](https://www.ruby-forum.com/u/jared)\ **Post date:** [July 6, 2015, 8:41pm UTC](https://www.ruby-forum.com/t/re-suppressing-uhd-prints/242606/2 "2015-07-06T20:41:50Z")
On 07/06/2015 07:25 PM, Jared D. wrote: > @Sebastion “Even if ’ uhd::msg::register\_handler’ would be exposed to python, > you > still can’t drop-in your own null-handler. Swig doesn’t support > callbacks in the target language (python).” > > This seems precisely what I have observed working with my example from my > question on 7/2/2015 “message passing: strobe or \_post?” I use a Python method as > a callback given to .set\_msg\_handler. This is certainly called when I use > the message strobe to input a message to the block, but not when using \_post. Is > this some new feature? Or am I wrong that the operation is the same? Well SWIG not supporting it (see [1]) doesn’t mean one can’t write custom code to run Python from the C end. Python blocks are implemented via a gateway [2] to do this. Sebastian [1] [SWIG-3.0 Documentation](http://www.swig.org/Doc3.0/SWIGDocumentation.html#SWIG_nn30) [2] [gnuradio/gnuradio-runtime/lib/block\_gateway\_impl.cc at master · gnuradio/gnuradio · GitHub](https://github.com/gnuradio/gnuradio/blob/master/gnuradio-runtime/lib/block_gateway_impl.cc) – Karlsruhe Institute of Technology (KIT) Communications Engineering Lab (CEL) Dipl.-Ing. Sebastian Koslowski Research Associate Kaiserstrae 12 Building 05.01 76131 Karlsruhe, Germany Phone: +49 721 608-46275 Fax: +49 721 608-46071 Email: [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) Web: [http://www.cel.kit.edu/](http://www.cel.kit.edu/) KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association