# Fwd: regarding your paper

**URL:** <https://www.ruby-forum.com/t/fwd-regarding-your-paper/241055>\
**Category:** GNU Radio\
**Created:** [May 11, 2014, 11:18am UTC](https://www.ruby-forum.com/t/fwd-regarding-your-paper/241055 "2014-05-11T11:18:17Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**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:** [May 11, 2014, 11:18am UTC](https://www.ruby-forum.com/t/fwd-regarding-your-paper/241055/1 "2014-05-11T11:18:17Z")

</div>

hi ,  
i have gone through bastin bloessl’s code for ieee\_802\_15\_4. i  
installed  
it in my ubuntu 12.04 having gnuradio v3.7 . it installed and i got the  
following error when i was trying to run the flowgraph.

Traceback (most recent call last):  
File “/home/cps/.grc\_gnuradio/ieee802\_15\_4\_phy.py”, line 16, in  
  
import ieee802\_15\_4  
File  
“/usr/local/lib/python2.7/dist-packages/ieee802\_15\_4/ **init**.py”,  
line 17, in   
from ieee802\_15\_4\_swig import \*  
File  
“/usr/local/lib/python2.7/dist-packages/ieee802\_15\_4/ieee802\_15\_4\_swig.py”,  
line 26, in   
\_ieee802\_15\_4\_swig = swig\_import\_helper()  
File  
“/usr/local/lib/python2.7/dist-packages/ieee802\_15\_4/ieee802\_15\_4\_swig.py”,  
line 22, in swig\_import\_helper  
\_mod = imp.load\_module(’\_ieee802\_15\_4\_swig’, fp, pathname,  
description)  
ImportError: /usr/local/lib/libgnuradio-ieee802\_15\_4.so: undefined  
symbol:  
\_ZN2gr6blocks12count\_bits32Ej

i have no idea what it means. is it the problem with count\_bits block.

looking forward for the reply.

thanks,  
lingeswar

---

<div class="post-metadata">

**Author:** ![lingeswar\_kandregul](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/f4b2a3/32.png) [@lingeswar\_kandregul](https://www.ruby-forum.com/u/lingeswar_kandregul)\
**Post date:** [May 11, 2014, 2:27pm UTC](https://www.ruby-forum.com/t/fwd-regarding-your-paper/241055/2 "2014-05-11T14:27:40Z")

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Hi Lingeswar,

> 

“/usr/local/lib/python2.7/dist-packages/ieee802\_15\_4/ieee802\_15\_4\_swig.py”,

> line 22, in swig\_import\_helper  
> \_mod = imp.load\_module(‘\_ieee802\_15\_4\_swig’, fp, pathname,  
> description)  
> ImportError: /usr/local/lib/libgnuradio-ieee802\_15\_4.so: undefined  
> symbol: \_ZN2gr6blocks12count\_bits32Ej

I guess libgnuradio-ieee802\_15\_4.so is not linked against  
libgnuradio-blocks.so. You can check that with

ldd libgnuradio-ieee802\_15\_4.so

Are you using the most recent version of 15.4? Linking should work  
latest since this commit

> <https://github.com/bastibl/gr-ieee802-15-4/commit/a586256ad5e3fe1cf8c998a68a7276adf6e2d691>

Best,  
Bastian