Python errors running flowgraph - first attempt

GNU Radio
1

Newbie to gnuradio. After struggling for a couple weeks with build
issues, I finally have a yocto-based build for an embedded x86_64
target. I’m trying to execute a flowgraph that I demonstrated
successfully on Ubuntu 14. I copied the resulting .grc file from
Ubuntu to the x86_64 target. It is based directly from gnuradio
tutorial, a broadcast FM receiver.

gnuradio-companion runs on my embedded x86_64 target, but issues three
XML parse errors on startup:

Preferences file: /home/root/.grc
Block paths:
/usr/share/gnuradio/grc/blocks
/usr/local/share/gnuradio/grc/blocks
/home/root/.grc_gnuradio

XML parser: Found 3 erroneous XML files while loading the block tree

Displaying these errors from Help shows all three are similar with the
text “Element <block|param>…does not follow DTD, expecting…”

Then gnuradio-companion starts up and displays my flowgraph.

When I try to ‘Run’ it, I get:

Showing: “/home/root/gr-tutorial-broadcast-fm-rx.grc”
Generating: “/home/root/my_gui.py”
Executing: “/home/root/my_gui.py”

Traceback (most recent call last):
File “/home/root/my_gui.py”, line 8, in
from PyQt4 import Qt
File “/usr/lib/python2.7/site-packages/PyQt4/Qt.py”, line 1
from PyQt4.QtCore import *\n

Looking at Qt.py, it contained 8 lines that looked like this:
from PyQt4.QtCore import *\n
… <repeated 7 more times with various modules>
SyntaxError: unexpected character after line continuation character

Once I “hacked” the ‘\n’ from these lines, and reran the flowgraph
using ‘Run’, now I get this:

Traceback (most recent call last):
File “/home/root/my_gui.py”, line 8, in
from PyQt4 import Qt
File “/usr/lib/python2.7/site-packages/PyQt4/Qt.py”, line 2, in

from PyQt4.QtDeclarative import *

ImportError: /usr/lib/python2.7/site-packages/PyQt4/QtDeclarative.so:
undefined symbol: _ZTI16QDeclarativeView

This looks like some type of package mismatch? I’m not a python guy :frowning:

My yocto-based build configuration looks like this:
meta-sdr: master
meta-python: dizzy
meta-oe: dizzy
oe-core: dizzy

Any advice is appreciated on how to resolve this.

Regards,

Chris H.inan

–
Life is like Linux - it never stands still.

2

On Thu, Feb 5, 2015 at 6:26 PM, Chris H.inan [email protected]
wrote:

Preferences file: /home/root/.grc
Then gnuradio-companion starts up and displays my flowgraph.
File “/usr/lib/python2.7/site-packages/PyQt4/Qt.py”, line 1
from PyQt4.QtCore import *\n

Looking at Qt.py, it contained 8 lines that looked like this:
from PyQt4.QtCore import *\n
… <repeated 7 more times with various modules>
SyntaxError: unexpected character after line continuation character

Once I “hacked” the ‘\n’ from these lines, and reran the flowgraph

Hi Chris,

That looks like maybe it’s a problem between code editors adding or
misinterpreting the line end character.

In general, though, we don’t recommend people actually run GRC on their
embedded devices. You want to build and debug everything on a host. If
using Python, you just copy over the resulting Python file to the device
you want to run on. If it’s a C++ project, you’d cross-compile and then
move the binary over. That would help with these issues, I think.

This looks like some type of package mismatch? I’m not a python guy :frowning:

Yes, looks like a version mismatch. Possibly between PyQT and QT or
something to do with QWT.

Chris H.inan

I’ll have to let Philip B. comment on this. But using dizzy and
meta-sdr’s master could be part of the problem. I’ve mostly stayed on
daisy
for the OE stuff, so I don’t have any knowledge of the version issues
here.
Though it’s probably time I move up to dizzy.

Tom