Re: QT GUI Label error in v 3.10.1.1

[Cinaed Simson]

I'd recommend adding

  export QT_QPA_PLATFORM=wayland

to your

  $HOME/.bash_profile

file or your

  $HOME/.bashrc

file - if you feel comfortable editing files on Linux.

I prefer the .bashrc since this were I place all my exports and group them all together.

However, the .bashrc isn't as tolerant to errors as the .bash_profile file.

In either case make a backup of the file before you edit the file.

You can check the results after you login again by typing
 
   echo $QT_QPA_PLATFORM

-- Cinaed

On 11/28/22 13:05, Jose Ruvalcaba wrote:

HI Cinaed and Jeff,

Sorry for the late reply. I checked if I had the qt-6 wayland and xwayland installed. Turns out I didn't have the qt6-wayland installed so I installed it. The issue still remained so I disabled wayland and it seemed to work. Just like what you guys saw, I stopped seeing the issue on my flowgraph. 

However, I attempted another flowgraph that used QT GUI Label and the issue came back. I have added the new flowgraph I created along with its generated code.

I am working from a WIndows machine that has  a Virtual Machine with Ubuntu 22.04. One quick question though: Where would I set the export QT_QPA_PLATFORM

Thanks,

Jose Ruvalcaba

On Thu, Nov 24, 2022 at 5:25 PM Cinaed Simson <cinaed.simson@gmail.com> wrote:

Hi Jose - I can run your script for hours without any issues on both GR 3.8 and 3.10.

Have you tried setting

  export QT_QPA_PLATFORM=wayland

as indicated in the first error message - to see if the script runs longer then 10 minutes?

My guess is if you eliminate the first exception the other exceptions will disappear.

Are you working from the console of a linux machine - or are you working from the console of a Windows machine - and then connecting to the a Linux machine by some method?

-- Cinaed


On Tue, Nov 22, 2022 at 10:23 PM Jose Ruvalcaba <joruvalc@gmail.com> wrote:

Hello,

I've been noticing an issue popping out everytime I stop running my flowgraph and I was wondering if someone had some insight on it. I have a flowgraph where a signal source is connected to a probe signal block. This block is constantly updating values and are being displayed using the QT GUI Label block. However, after running my flowgraph for about 10 minutes I get the following error:

Executing: /usr/bin/python3 -u /home/spacerfvm/Documents/GNURadio_3.10_flowgraphs/func_probe_test.py

Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.

Exception in thread Thread-1 (_amp_probe):

Traceback (most recent call last):

  File "/home/spacerfvm/Documents/GNURadio_3.10_flowgraphs/func_probe_test.py", line 150, in _amp_probe

    self.doc.add_next_tick_callback(functools.partial(self.set_amp,val))

  File "/usr/lib/python3/dist-packages/gnuradio/gr/hier_block2.py", line 88, in __getattr__

    return getattr(self._impl, name)

AttributeError: 'gnuradio.gr.gr_python.top_block_pb' object has no attribute 'doc'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):

  File "/usr/lib/python3.10/threading.py", line 1016, in _bootstrap_inner

    self.run()

  File "/usr/lib/python3.10/threading.py", line 953, in run

    self._target(*self._args, **self._kwargs)

  File "/home/spacerfvm/Documents/GNURadio_3.10_flowgraphs/func_probe_test.py", line 152, in _amp_probe

    self.set_amp(val)

  File "/home/spacerfvm/Documents/GNURadio_3.10_flowgraphs/func_probe_test.py", line 182, in set_amp

    self.set_variable_qtgui_label_0(self.amp)

  File "/home/spacerfvm/Documents/GNURadio_3.10_flowgraphs/func_probe_test.py", line 189, in set_variable_qtgui_label_0

    Qt.QMetaObject.invokeMethod(self._variable_qtgui_label_0_label, "setText", Qt.Q_ARG("QString", str(self._variable_qtgui_label_0_formatter(self.variable_qtgui_label_0))))

RuntimeError: wrapped C/C++ object of type QLabel has been deleted

It seems that my issue is related to the QT GUI Label block because when I remove it and add say QT GUI Number sink, this issue doesn't appear.

Has anyone experienced this issue? If so, would anyone be able to steer me in the direction to fix it? I am currently running on Ubuntu 22.04 and am running GNU RADIO 3.10.1.1 which I installed using sudo apt-get install. I've also attached the flowgraph I am talking about.

Thanks,

Jose Ruvalcaba