# Gr-bluetooth

**URL:** <https://www.ruby-forum.com/t/gr-bluetooth/230875>\
**Category:** GNU Radio\
**Created:** [July 10, 2014, 2:38am UTC](https://www.ruby-forum.com/t/gr-bluetooth/230875 "2014-07-10T02:38:53Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\
**Post date:** [July 10, 2014, 2:38am UTC](https://www.ruby-forum.com/t/gr-bluetooth/230875/1 "2014-07-10T02:38:53Z")

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Hello all,

I’ve updated the gr-bluetooth [1] code to be compatible with GNU Radio  
3.7. I’m trying to use it, but there’s a segmentation fault that I need  
to figure out. Has anyone done anything with gr-bluetooth recently? Does  
anyone know if the current version of the code is even functional with  
GNU Radio 3.6? Were there changes in GNU Radio between 3.6 and 3.7 that  
would cause this issue to appear? My specific issue is outlined below.

I have encountered a segmentation fault issue in the  
gr::bluetooth::multi\_block code (which all the other gr-bluetooth blocks  
use) that did not appear while running the included QA code (though I’m  
not sure how reliable the test code was). I’ve spent the past couple  
days trying to track down with GDB what exactly is going wrong, so that  
I can fix it (the code looks fine to me, nothing is standing out as a  
big issue). From what I’ve gathered so far, it appears the issue is with  
“gr\_vector\_void\_star& out”, an input to multi\_block::channel\_samples().  
I don’t have a lot of experience with debugging, so if anyone has any  
suggestions about what to look for when tracking down segmentation  
faults (my understanding is that  
memory is being accessed which should not be accessed by the process), I  
would appreciate them.

Best,  
Orin

[1] [GitHub - greatscottgadgets/gr-bluetooth: A Bluetooth receiver implementation for GNU Radio](https://github.com/greatscottgadgets/gr-bluetooth)

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**Author:** ![Orin\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/90ced4/32.png) [@Orin\_L](https://www.ruby-forum.com/u/Orin_L)\
**Post date:** [July 10, 2014, 2:44am UTC](https://www.ruby-forum.com/t/gr-bluetooth/230875/2 "2014-07-10T02:44:51Z")

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Orin L. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) writes:

> gr::bluetooth::multi\_block code (which all the other gr-bluetooth blocks  
> would appreciate them.

You may want to have a look at valgrind[1] which in an invaluable tool  
in tracking down this sort of issue. Be warned that it will slow things  
down by quite a bit but it will probably tell you exactly what you need  
to know.

Cheers,

- Ben

[1] [http://valgrind.org/](http://valgrind.org/)

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**Author:** ![Orin\_L](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/o/90ced4/32.png) [@Orin\_L](https://www.ruby-forum.com/u/Orin_L)\
**Post date:** [July 10, 2014, 11:23am UTC](https://www.ruby-forum.com/t/gr-bluetooth/230875/3 "2014-07-10T11:23:00Z")

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On 07/10/2014 12:05 AM, Orin L. wrote:

> faults (my understanding is that  
> memory is being accessed which should not be accessed by the process), I  
> would appreciate them.

If you build GNU Radio with debug symbols and follow the instructions on  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsDebugging](http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsDebugging),  
you can figure out exactly where the segfault is happening; that’ll help  
you fix the problem.

M