# No attribute 'message\_sink'

**URL:** <https://www.ruby-forum.com/t/no-attribute-message-sink/237252>\
**Category:** GNU Radio\
**Created:** [November 1, 2013, 9:01am UTC](https://www.ruby-forum.com/t/no-attribute-message-sink/237252 "2013-11-01T09:01:37Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [November 1, 2013, 9:01am UTC](https://www.ruby-forum.com/t/no-attribute-message-sink/237252/1 "2013-11-01T09:01:37Z")

</div>

Hi,

I’m using USRP N210 with LFRX.

I installed uhd and gnuradio with build-gnuradio script without any  
problem.

However, when I run an application, it has such error message:

```
self.sink = gr.message_sink(gr.sizeof_short*2, self.queue, False)

```

AttributeError: ‘module’ object has no attribute ‘message\_sink’

Several months ago, I installed on several computers with the  
build-gnuradio  
script and run the same application, and there was no such problem.

Has gnuradio changed something recently?

Best regards,

Wu

---

<div class="post-metadata">

**Author:** ![Ting\_Wu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/3bc359/32.png) [@Ting\_Wu](https://www.ruby-forum.com/u/Ting_Wu)\
**Post date:** [November 1, 2013, 10:24am UTC](https://www.ruby-forum.com/t/no-attribute-message-sink/237252/2 "2013-11-01T10:24:34Z")

</div>

Hi Wu,  
yes, something has changed: GNU Radio made a version progression from  
3.6 to 3.7. Part of this progress was that the standards blocks are now  
part of the “blocks” module, and no longer of the “gr” module.  
Please refer to the official GR wiki to learn about conversion from 3.6  
to 3.7.

Greetings,  
Marcus

---

<div class="post-metadata">

**Author:** ![Ting\_Wu](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/3bc359/32.png) [@Ting\_Wu](https://www.ruby-forum.com/u/Ting_Wu)\
**Post date:** [November 2, 2013, 7:58am UTC](https://www.ruby-forum.com/t/no-attribute-message-sink/237252/3 "2013-11-02T07:58:32Z")

</div>

Hi Marcus,

Thanks!  
I changed the line to " self.sink =  
blocks.message\_sink(gr.sizeof\_short\*2, self.queue, False)"  
and now it works.

Wu