# How to change a flowgraph in c++ dynamically

**URL:** <https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104>\
**Category:** GNU Radio\
**Created:** [May 13, 2014, 11:07am UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104 "2014-05-13T11:07:44Z")\
**Posts on this page:** 6\
**Page:** 1

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**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:** [May 13, 2014, 11:07am UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104/1 "2014-05-13T11:07:44Z")

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Hi everybody,

I was wonder why I can’t make a class of topblock in c++ like in python  
as  
said here:

[http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsWritePythonApplications](http://gnuradio.org/redmine/projects/gnuradio/wiki/TutorialsWritePythonApplications)

Then I think, I can control the flowgraph, start or stop it , disconnect  
or  
connect blocks and anything else .

Any idea?

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**Author:** ![mostafa\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/5e9695/32.png) [@mostafa\_a](https://www.ruby-forum.com/u/mostafa_a)\
**Post date:** [May 13, 2014, 2:58pm UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104/2 "2014-05-13T14:58:30Z")

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On 13.05.2014 11:05, Mostafa A. wrote:

> Any idea?  
> It’s pretty much the same, just in C++.  
> Have a look at the c++ examples in the source tree, that’ll get you  
> started.

M

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**Author:** ![mostafa\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/5e9695/32.png) [@mostafa\_a](https://www.ruby-forum.com/u/mostafa_a)\
**Post date:** [May 15, 2014, 4:41am UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104/3 "2014-05-15T04:41:23Z")

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It’s better to say in this way: _how could I use stop(), start(),  
lock(),  
unlock() of the topblock methods? Is there any example of them?_

Thanks,

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**Author:** ![mostafa\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/5e9695/32.png) [@mostafa\_a](https://www.ruby-forum.com/u/mostafa_a)\
**Post date:** [May 16, 2014, 1:16am UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104/4 "2014-05-16T01:16:01Z")

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Hi Marcus,

what do you mean by \*“run to completion” \*?

best,  
Mostafa

On Thu, May 15, 2014 at 10:40 AM, Mostafa A.

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**Author:** ![mostafa\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/5e9695/32.png) [@mostafa\_a](https://www.ruby-forum.com/u/mostafa_a)\
**Post date:** [May 16, 2014, 6:01am UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104/5 "2014-05-16T06:01:34Z")

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Hi Marcus,

Thank you,

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<div class="post-metadata">

**Author:** ![mostafa\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/5e9695/32.png) [@mostafa\_a](https://www.ruby-forum.com/u/mostafa_a)\
**Post date:** [May 16, 2014, 2:34am UTC](https://www.ruby-forum.com/t/how-to-change-a-flowgraph-in-c-dynamically/241104/6 "2014-05-16T02:34:30Z")

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Hi Mostafa,  
I mean the run option “run to completion” in the GRC. GRC is like LEGO  
for  
communication engineers, if you play around with it, you’ll soon be  
having  
fun and have an easier time understanding hints like this 😉  
See [http://imgur.com/YPUvyzm](http://imgur.com/YPUvyzm)

Greetings,  
Marcus