# Top block edge list

**URL:** <https://www.ruby-forum.com/t/top-block-edge-list/232310>\
**Category:** GNU Radio\
**Created:** [October 1, 2014, 11:00pm UTC](https://www.ruby-forum.com/t/top-block-edge-list/232310 "2014-10-01T23:00:02Z")\
**Posts on this page:** 2\
**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:** [October 1, 2014, 11:00pm UTC](https://www.ruby-forum.com/t/top-block-edge-list/232310/1 "2014-10-01T23:00:02Z")

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Hello All,  
I’m trying to access the data inside the top block class, from a custom  
function or at the very least print out some of it as a test. Is there a  
way to see the data in the top block edge\_list() before running  
top\_block.start()? I’d like to access this without modifying any of the  
code in gnuradio-runtime so just using already provided functions in  
top\_block.  
Thanks,  
Ryan

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**Author:** ![rmac217](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/bc8723/32.png) [@rmac217](https://www.ruby-forum.com/u/rmac217)\
**Post date:** [October 2, 2014, 12:52am UTC](https://www.ruby-forum.com/t/top-block-edge-list/232310/2 "2014-10-02T00:52:38Z")

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Ryan,

You can print the edge list using

print tb.edge\_list()

BUT, it’s not populated until after tb.start(). You can either wait  
until after tb.start(), or you can use

print tb.dot\_graph()

before tb.start(). It’s meant to be input to dot (graphviz) but it’s  
human readable. “dotty” didn’t actually parse it right, but I could have  
done something wrong there.

- Jeff