# Executing the flow graph: window closes immediatly

**URL:** <https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118>\
**Category:** GNU Radio\
**Created:** [August 23, 2015, 10:06pm UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118 "2015-08-23T22:06:42Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![Rafa\_F](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/958977/32.png) [@Rafa\_F](https://www.ruby-forum.com/u/Rafa_F)\
**Post date:** [August 23, 2015, 10:06pm UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/1 "2015-08-23T22:06:42Z")

</div>

Hello,

I’m totally new to the gnu radio project and trying my first steps into  
the world of SDR.

At this moment i ran into a problem: I followed the steps of the  
tutorial at  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC)

I made the flowchart exactly as described in the tutorial, but when i  
try to execute the flow graph, a window appears and directly closes.

When I try to run the code directly from the terminal i get following  
message: Segmentation fault (core dumped)

I’m running Ubuntu 14.04 LTS.

How can I fix this issue?

Regards

Nick

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 23, 2015, 10:31pm UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/2 "2015-08-23T22:31:15Z")

</div>

Hi Nick,

segmentation fault is a severe error; it means that the program you  
generated tried to access memory that wasn’t there. The error really  
doesn’t say anything more.  
We haven’t seen such error in released GNU Radio versions lately.

My guess therefore is that there might be something wrong with your set  
up instead.  
How did you install GNU Radio? If you’ve installed it from source, or  
build-gnuradio, or pybombs you _must not_ install gnuradio from Ubuntu’s  
package archives.

Best regards,  
Marcus

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 25, 2015, 10:45am UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/3 "2015-08-25T10:45:08Z")

</div>

That does sound correct; so we need to really look deeper into what goes  
wrong in your flowgraph. Which one from that tutorial are we talking  
about specifically? Can you share the .grc file?

Best regards,  
Marcus

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 25, 2015, 11:14am UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/4 "2015-08-25T11:14:57Z")

</div>

I followed the tutorial on [gnuradio.org](http://gnuradio.org) (correct link:  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC) )

This is the particular flowchart we’re talking about:  
[![](https://raw.githubusercontent.com/gnuradio/gr-tutorial/master/examples/tutorial2/images/tutorial_two_1.png) ](https://raw.githubusercontent.com/gnuradio/gr-tutorial/master/examples/tutorial2/images/tutorial_two_1.png)

In attachment is the .grc file.

Best regards,

Nick

----- Oorspronkelijk bericht -----

Van: “Marcus Müller” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Aan: “nick meynen” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid), “GNURadio D.ion List”  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Verzonden: Maandag 24 augustus 2015 15:17:40  
Onderwerp: Re: [Discuss-gnuradio] Executing the flow graph: window  
closes immediatly

That does sound correct; so we need to really look deeper into what goes  
wrong in your flowgraph. Which one from that tutorial are we talking  
about specifically? Can you share the .grc file?

Best regards,  
Marcus

On 08/24/2015 08:26 AM, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

Hi Marcus,

I installed the gnu radio from the command “sudo apt-get install  
gnuradio” trough the terminal.

This installation went smooth and I did not observe any problems.

After this I started to follow the tutorial (  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC) )  
but on step 2.1.2 the cmake command failed so i needed to install the  
cmake and doxygen packages.

Best regards,

Nick

----- Oorspronkelijk bericht -----

Van: “Marcus Müller” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Aan: [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Verzonden: Zondag 23 augustus 2015 22:28:38  
Onderwerp: Re: [Discuss-gnuradio] Executing the flow graph: window  
closes immediatly

Hi Nick,

segmentation fault is a severe error; it means that the program you  
generated tried to access memory that wasn’t there. The error really  
doesn’t say anything more.  
We haven’t seen such error in released GNU Radio versions lately.

My guess therefore is that there might be something wrong with your set  
up instead.  
How did you install GNU Radio? If you’ve installed it from source, or  
build-gnuradio, or pybombs you _must not_ install gnuradio from Ubuntu’s  
package archives.

Best regards,  
Marcus

On 23.08.2015 22:05, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hello,
> 
> I’m totally new to the gnu radio project and trying my first steps into  
> the world of SDR.
> 
> At this moment i ran into a problem: I followed the steps of the  
> tutorial at  
> [http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC)
> 
> I made the flowchart exactly as described in the tutorial, but when i  
> try to execute the flow graph, a window appears and directly closes.
> 
> When I try to run the code directly from the terminal i get following  
> message: Segmentation fault (core dumped)
> 
> I’m running Ubuntu 14.04 LTS.
> 
> How can I fix this issue?
> 
> Regards
> 
> Nick
> 
> * * *
> 
> Discuss-gnuradio mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)
> 
> * * *
> 
> Discuss-gnuradio mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)
> 
> > **[Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)**

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 25, 2015, 11:37am UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/5 "2015-08-25T11:37:44Z")

</div>

Hi Nick,

I don’t know whether this is good or bad news: On my machine, this runs  
beautifully.  
I don’t have Ubuntu 14.04 LTS at hand, but since that is one of the main  
platforms that people use to work with GNU Radio, a systematic error in  
GNU Radio would most likely have been spotted already.

Now, I’d like to ask you to run the flowgraph with GDB, to get more  
debugging info. Is that alright with you?

sudo apt-get install gdb #if you don’t have gdb installed  
gdb python /path/to/flowgraph.py #path is displayed in the GRC console  
when you hit the “generate” button.  
(gdb) run

Best regards,  
Marcus

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 25, 2015, 2:04pm UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/6 "2015-08-25T14:04:58Z")

</div>

Hi Nick,

I’d personally say that the GNU Radio packages in Ubuntu should be  
pretty up to date (thanks, Maitland!), but the UHD in Ubuntu is  
extremely old, so if you want to use USRPs, you can’t use Ubuntu’s GNU  
Radio.  
Since building isn’t that hard nowadays, and you had bad experiences  
with the Ubuntu package, I’d just try using pybombs [1]:

git clone --recursive [GitHub - gnuradio/pybombs: PyBOMBS (Python Build Overlay Managed Bundle System) is the GNU Radio install management system for resolving dependencies and pulling in out-of-tree projects.](https://github.com/pybombs/pybombs.git) && cd  
pybombs && ./pybombs install gnuradio

You should be able to answer all questions with the default (just  
 your way through the dialog), then after everything is complete:

./pybombs env

and add the generated file to your bashrc:

echo “source /setup\_env.sh” \>\> ~/.bashrc

Open up a new terminal and run gnuradio-companion.

Best regards,  
Marcus

[1] [http://pybombs.info](http://pybombs.info)

---

<div class="post-metadata">

**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [August 25, 2015, 11:41am UTC](https://www.ruby-forum.com/t/executing-the-flow-graph-window-closes-immediatly/243118/7 "2015-08-25T11:41:50Z")

</div>

Hi Marcus,

I’m sorry i made just a terrible mistake: i reply’d to the wrong tread.

This was my answer:

Marcus,

I just saw i was still running a 32 bit installation of linux. I just  
removed my old installation and busy reinstalling a fresh Ubuntu 14.04  
LTS.

What instalation way is best? Installing by the sudo apt-get install  
command or just build my own version?

best regards,

Nick

----- Oorspronkelijk bericht -----

Van: “Marcus Müller” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Aan: “nick meynen” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Cc: “GNURadio D.ion List” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Verzonden: Maandag 24 augustus 2015 18:32:58  
Onderwerp: Re: [Discuss-gnuradio] Executing the flow graph: window  
closes immediatly

Hi Nick,

I don’t know whether this is good or bad news: On my machine, this runs  
beautifully.  
I don’t have Ubuntu 14.04 LTS at hand, but since that is one of the main  
platforms that people use to work with GNU Radio, a systematic error in  
GNU Radio would most likely have been spotted already.

Now, I’d like to ask you to run the flowgraph with GDB, to get more  
debugging info. Is that alright with you?

sudo apt-get install gdb #if you don’t have gdb installed  
gdb python /path/to/flowgraph.py #path is displayed in the GRC console  
when you hit the “generate” button.  
(gdb) run

Best regards,  
Marcus

On 08/24/2015 05:48 PM, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

I followed the tutorial on [gnuradio.org](http://gnuradio.org) (correct link:  
[http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC) )

This is the particular flowchart we’re talking about:  
[![](https://raw.githubusercontent.com/gnuradio/gr-tutorial/master/examples/tutorial2/images/tutorial_two_1.png) ](https://raw.githubusercontent.com/gnuradio/gr-tutorial/master/examples/tutorial2/images/tutorial_two_1.png)

In attachment is the .grc file.

Best regards,

Nick

----- Oorspronkelijk bericht -----

Van: “Marcus Müller” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Aan: “nick meynen” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) , “GNURadio D.ion List”  
[removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Verzonden: Maandag 24 augustus 2015 15:17:40  
Onderwerp: Re: [Discuss-gnuradio] Executing the flow graph: window  
closes immediatly

That does sound correct; so we need to really look deeper into what goes  
wrong in your flowgraph. Which one from that tutorial are we talking  
about specifically? Can you share the .grc file?

Best regards,  
Marcus

On 08/24/2015 08:26 AM, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:

> Hi Marcus,
> 
> I installed the gnu radio from the command “sudo apt-get install  
> gnuradio” trough the terminal.
> 
> This installation went smooth and I did not observe any problems.
> 
> After this I started to follow the tutorial (  
> [http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC) )  
> but on step 2.1.2 the cmake command failed so i needed to install the  
> cmake and doxygen packages.
> 
> Best regards,
> 
> Nick
> 
> ----- Oorspronkelijk bericht -----
> 
> Van: “Marcus Müller” [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> Aan: [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> Verzonden: Zondag 23 augustus 2015 22:28:38  
> Onderwerp: Re: [Discuss-gnuradio] Executing the flow graph: window  
> closes immediatly
> 
> Hi Nick,
> 
> segmentation fault is a severe error; it means that the program you  
> generated tried to access memory that wasn’t there. The error really  
> doesn’t say anything more.  
> We haven’t seen such error in released GNU Radio versions lately.
> 
> My guess therefore is that there might be something wrong with your set  
> up instead.  
> How did you install GNU Radio? If you’ve installed it from source, or  
> build-gnuradio, or pybombs you _must not_ install gnuradio from Ubuntu’s  
> package archives.
> 
> Best regards,  
> Marcus
> 
> On 23.08.2015 22:05, [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote:
> 
> > Hello,
> > 
> > I’m totally new to the gnu radio project and trying my first steps into  
> > the world of SDR.
> > 
> > At this moment i ran into a problem: I followed the steps of the  
> > tutorial at  
> > [http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided\_Tutorial\_GRC](http://gnuradio.org/redmine/projects/gnuradio/wiki/Guided_Tutorial_GRC)
> > 
> > I made the flowchart exactly as described in the tutorial, but when i  
> > try to execute the flow graph, a window appears and directly closes.
> > 
> > When I try to run the code directly from the terminal i get following  
> > message: Segmentation fault (core dumped)
> > 
> > I’m running Ubuntu 14.04 LTS.
> > 
> > How can I fix this issue?
> > 
> > Regards
> > 
> > Nick
> > 
> > * * *
> > 
> > Discuss-gnuradio mailing list [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)
> > 
> > * * *
> > 
> > Discuss-gnuradio mailing list  
> > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)
> > 
> > > **[Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio)**