# Using qtgui for plotting constellations

**URL:** <https://www.ruby-forum.com/t/using-qtgui-for-plotting-constellations/240910>\
**Category:** GNU Radio\
**Created:** [May 6, 2014, 12:27pm UTC](https://www.ruby-forum.com/t/using-qtgui-for-plotting-constellations/240910 "2014-05-06T12:27:16Z")\
**Posts on this page:** 1\
**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 6, 2014, 12:27pm UTC](https://www.ruby-forum.com/t/using-qtgui-for-plotting-constellations/240910/1 "2014-05-06T12:27:16Z")

</div>

hello everybody,

I wanted to use constellation plot of gnuradio in my top block in c++. I  
actually use qtcreator in ubuntu and gnuradio 3.7.3. After I found out  
that I must add “-lgnuradio-qtgui” to the .pro file of qtcreator for  
using qtgui of gnuradio, I ran the program but it didn’t open any GUI!!!

my code is like this :

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////  
#include \<gnuradio/qtgui/const\_sink\_c.h\>

#include \<QtGui/QApplication\>  
#include \<qapplication.h\>  
#include

using namespace gr;

int main()  
{  
// some blocks here …

```
 qtgui::const_sink_c::sptr constellation =

```

qtgui::const\_sink\_c::make(10, “constellation”, 1, NULL);

```
  // some connections ....

  tb->run();

  return 0;

```

}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

What is the problem!? Why I can’t see any GUI?

best