# Public method in out of tree module **URL:** \ **Category:** GNU Radio\ **Created:** [November 22, 2013, 4:53pm UTC](https://www.ruby-forum.com/t/public-method-in-out-of-tree-module/237657 "2013-11-22T16:53:02Z")\ **Posts on this page:** 3\ **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:** [November 22, 2013, 4:53pm UTC](https://www.ruby-forum.com/t/public-method-in-out-of-tree-module/237657/1 "2013-11-22T16:53:02Z")
Hello, I am trying to create a block that has a publicly accessible method and am having trouble accessing the method from within Python. Here is a simple example of my process. First, I boot Gnuradio Live DVD, Ubutnu 12.04, Gnuradio 3.7.2 Second, i create a new module according to: [http://gnuradio.org/redmine/projects/gnuradio/wiki/OutOfTreeModules](http://gnuradio.org/redmine/projects/gnuradio/wiki/OutOfTreeModules) > gr\_modtool newmod testmod > cd gr-testmod > gr\_modtool add -t general testblock (empty argument list, default answers) > vim lib/testblock\_impl.cc (Edit this to the same as the square\_ff.cc code > from the example) > mkdir build > cd build > cmake …/ > make > sudo make install > sudo ldconfig This works fine, I can verify the block is working correctly. Then I edit the public header file to add a pure virtual method pub() vim include/testmod/testblock.h > … > public: > virtual int pub() = 0; > … Then I edit the private header file to implement the method > … > public: > int pub(){ return 1; } > … If I build this, it will make and install just fine. The only problem comes when I run python like so > import testmod > b = testmod.testblock() > b.pub() I get the following error: > AttributeError: ‘testblock\_sptr’ object has no attribute ‘pub’ I’ve tried following the examples of in tree blocks, but just cannot seem to be able to access pub() from python. Am I missing an include, or something? Thank you, Dirk ---
**Author:** ![Dirk\_Van\_Bruggen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58956e/32.png) [@Dirk\_Van\_Bruggen](https://www.ruby-forum.com/u/Dirk_Van_Bruggen)\ **Post date:** [November 22, 2013, 5:21pm UTC](https://www.ruby-forum.com/t/public-method-in-out-of-tree-module/237657/2 "2013-11-22T17:21:40Z")
On Fri, Nov 22, 2013 at 10:51:22AM -0500, Dirk Van Bruggen wrote: > I’ve tried following the examples of in tree blocks, but just cannot seem > to be able to access pub() from python. Am I missing an include, or > something? Just to make sure, did you rebuild everything (including SWIG bindings)? Are you accessing pub() from QA code? If not, did you reinstall afterwards? MB – Karlsruhe Institute of Technology (KIT) Communications Engineering Lab (CEL) Dipl.-Ing. Martin B. Research Associate Kaiserstraße 12 Building 05.01 76131 Karlsruhe Phone: +49 721 608-43790 Fax: +49 721 608-46071 www.cel.kit.edu KIT – University of the State of Baden-Württemberg and National Laboratory of the Helmholtz Association ---
**Author:** ![Dirk\_Van\_Bruggen](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58956e/32.png) [@Dirk\_Van\_Bruggen](https://www.ruby-forum.com/u/Dirk_Van_Bruggen)\ **Post date:** [November 22, 2013, 5:25pm UTC](https://www.ruby-forum.com/t/public-method-in-out-of-tree-module/237657/3 "2013-11-22T17:25:11Z")
On 11/22/2013 07:51 AM, Dirk Van Bruggen wrote: > I’ve tried following the examples of in tree blocks, but just cannot > seem to be able to access pub() from python. Am I missing an include, > or something? There is an bug in the OOT build system where, after having compiled once, changes to public header files don’t result in remaking the dependent SWIG library. A workaround is to do make clean, then make again.