Re: [Discuss-gnuradio] QTGUI Issue

[Richard Bell]

Another update: I've managed to get the libqwt.so files isolated to the pybombs install directories:

address@hidden lib]$ sudo find / -name '*libqwt.so.5*'
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5.2.0
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5.2
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5
/home/tsvcis/Documents/target/lib/libqwt.so.5.2.0
/home/tsvcis/Documents/target/lib/libqwt.so.5.2
/home/tsvcis/Documents/target/lib/libqwt.so.5

but after all of this, I'm in the same boat as when we started. I get the following undefined symbol error when trying to use a QT block in grc:

ImportError: /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0: undefined symbol: _ZN7QwtPlot16staticMetaObjectE

I could use some more debug help as I'm out of ideas. I've made sure the only rpms installed related to qt are the base installs of qt3 and qt4 that comes with my CentOS 6.6 distro. All the other qt related things, qwt, qwt-devel, pyqwt and pyqwt-devel, are installed by pybombs from source.

One not obvious effect I've found is that if I try and import qtgui, I get the following error:

address@hidden lib]$ python
Python 2.6.6 (r266:84292, Jan 22 2014, 09:42:36)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import gnuradio
>>> from gnuradio import qtgui
Segmentation fault (core dumped)
address@hidden lib]$

However, if I import wxgui first, and then try to import qtgui, I get the symbol error I normally see in grc:

address@hidden lib]$ python
Python 2.6.6 (r266:84292, Jan 22 2014, 09:42:36)
[GCC 4.4.7 20120313 (Red Hat 4.4.7-4)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import gnuradio
>>> from gnuradio import wxgui
>>> from gnuradio import qtgui
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tsvcis/Documents/target/lib64/python2.6/site-packages/gnuradio/qtgui/__init__.py", line 34, in <module>
    from qtgui_swig import *
  File "/home/tsvcis/Documents/target/lib64/python2.6/site-packages/gnuradio/qtgui/qtgui_swig.py", line 26, in <module>
    _qtgui_swig = swig_import_helper()
  File "/home/tsvcis/Documents/target/lib64/python2.6/site-packages/gnuradio/qtgui/qtgui_swig.py", line 22, in swig_import_helper
    _mod = imp.load_module('_qtgui_swig', fp, pathname, description)
ImportError: /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0: undefined symbol: _ZN7QwtPlot16staticMetaObjectE
>>>

I'm only mentioning it in the chance it reveals something to someone.

Appreciate the help,
Rich

On Mon, Jan 26, 2015 at 5:47 PM, Richard Bell <address@hidden> wrote:

Latest update: After uninstalling all the qwt and pyqwt that were installed by yum, I tried a clean pybombs install, with everything installed from source, and it completed.

Further debug commands now look like this:

address@hidden ~]$ ldd /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0 | grep qwt
    libqwt.so.5 => /home/tsvcis/Documents/target/lib/libqwt.so.5 (0x00007f414c468000)

Searching for libqwt.so.5 revelas:

address@hidden ~]$ sudo find / -name 'libqwt.so.5*'
[sudo] password for tsvcis:
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5.2.0
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5.2
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5
/home/tsvcis/Documents/target/lib/libqwt.so.5.2.0
/home/tsvcis/Documents/target/lib/libqwt.so.5.2
/home/tsvcis/Documents/target/lib/libqwt.so.5
/usr/lib64/libqwt.so.5

The major difference between now and before is the absence of libqwt.so.5.1.1 files in /usr/lib64.

When I try to import qtgui, I get am still not able to.

>>> import gnuradio
>>> from gnuradio import qtgui
Segmentation fault (core dumped)
address@hidden ~]$

When I start grc and try to run a flowgraph with a qt widget I get the following error:

ImportError: /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0: undefined symbol: _ZN7QwtPlot16staticMetaObjectE

Executing the following has no effect:

export LD_PRELOAD=/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5

And executing the following:
export LD_PRELOAD=/usr/lib64/libqwt.so.5

leads to the following error when I start the python interpreter:
address@hidden build]$ export LD_PRELOAD=/usr/lib64/libqwt.so.5
address@hidden build]$ echo $LD_PRELOAD
/usr/lib64/libqwt.so.5
address@hidden build]$ python
ERROR: ld.so: object '/usr/lib64/libqwt.so.5' from LD_PRELOAD cannot be preloaded: ignored.

This is a difference from before, as only the appropriate library path seems to have an effect. But the bottom line is the same, qtgui does not work.

Rich

On Mon, Jan 26, 2015 at 3:48 PM, Richard Bell <address@hidden> wrote:

Executing 'export LD_PRELOAD=/usr/lib64/libqwt.so.5' allows me to run 'from gnuradio import qtgui' from a python prompt successfully. However, when I start grc and attempt to run a flowgraph as a test, I still get this error:

AttributeError: 'module' object has no attribute 'QWidget'

I uninstalled all the qwt and pyqwt modules and all components pybombs installed and started over.

I watched the qwt install closely. Pybombs installs through rpm the following:

PyQwt-5.2.0

PyQwt-devel-5.2.0

qwt-5.1.1

qwt-devel-5.1.1

It first identified qwt-5.1.1 as being an invalid version number, but when I ran pybombs install again, it used those versions that the rpm had to install. I'm not sure why it allows itself to download invalid versions.

If I try and force an install from source, it fails on pyqwt. I attempted to debug that further and got as far as configuring sip manually to overcome a sip import error that causes the 'source configure.py' step of pyqwt to fail. This then lead to several qt errors, at which point I stopped.

I'm struggling to figure out a solution.

Rich

On Mon, Jan 26, 2015 at 2:10 PM, Marcus Müller <address@hidden> wrote:

As it seems, at compile time, the 5.1.1 version was used, whilst at runtime the 5.2.0 version from your ~/Documents/target prefix seems to be found. That's a bit strange, since pybombs should use the qwt version that it downloaded (ie. 5.2.0 in your case). Maybe it's all the other way around...

If you

export LD_PRELOAD=/usr/lib64/libqwt.so.5

before running your GNU Radio application from the same terminal, does it help? what about using export LD_PRELOAD=/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5 ?

Greetings,
Marcus

On 01/26/2015 10:46 PM, Richard Bell wrote:

OK Marcus. The shared object file does exist in two directories. Full output of comands below, with matches bolded:

ldd /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0 | grep qwt

    libqwt.so.5 => /home/tsvcis/Documents/target/lib/libqwt.so.5 (0x00007f5d2a4c1000)


address@hidden ~]$ sudo find / -name 'libqwt.so.5*'
[sudo] password for tsvcis:
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5.2.0
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5.2
/home/tsvcis/Documents/pybombs/src/qwt5/lib/libqwt.so.5
/home/tsvcis/Documents/target/lib/libqwt.so.5.2.0
/home/tsvcis/Documents/target/lib/libqwt.so.5.2
/home/tsvcis/Documents/target/lib/libqwt.so.5
/usr/lib64/libqwt.so.5
/usr/lib64/libqwt.so.5.1.1
/usr/lib64/libqwt.so.5.1

The only thing I could think to do was rename the files in /usr/lib64. I don't see this as having an effect. What should I do to resolve this from here?

Thanks a lot,
Rich

On Mon, Jan 26, 2015 at 11:31 AM, Marcus Müller <address@hidden> wrote:

Hi Richard,

this looks like you've installed a "good" version of QWT, which is used when building GNU Radio, but when running a GNU Radio program, a different version of the QWT library is loaded, which leads to missing symbols.

My first approach would be to run ldd on /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0 , and see which qwt lib linux will try to load at runtime:
ldd /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0|grep qwt.

Then search for files that have the same base name, in this case libqwt.so .

Greetings,
Marcus

On 01/26/2015 07:59 PM, Richard Bell wrote:

Problem: I can't use qtgui blocks. Wxgui blocks work. My system is CentOS 6.6 running gnuradio 3.7.6 installed using pybombs.

Debug: I've run cmake in pybombs/gnuradio/src/build to make sure qtgui was enabled during install, and it is. The only gnuradio components disabled that are listed by cmake are doxygen, sphinx, gr-comedi and gr-zeromq.

I then opened a terminal to test library imports. I can 'import gnuradio' and I can 'from gnuradio import wxgui', as you would expect. When I try, 'from gnuradio import qtgui', I get the following output:

>>> import gnuradio
>>> from gnuradio import wxgui
>>> from gnuradio import qtgui
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/tsvcis/Documents/target/lib64/python2.6/site-packages/gnuradio/qtgui/__init__.py", line 34, in <module>
    from qtgui_swig import *
  File "/home/tsvcis/Documents/target/lib64/python2.6/site-packages/gnuradio/qtgui/qtgui_swig.py", line 26, in <module>
    _qtgui_swig = swig_import_helper()
  File "/home/tsvcis/Documents/target/lib64/python2.6/site-packages/gnuradio/qtgui/qtgui_swig.py", line 22, in swig_import_helper
    _mod = imp.load_module('_qtgui_swig', fp, pathname, description)
ImportError: /home/tsvcis/Documents/target/lib64/libgnuradio-qtgui-3.7.7git.so.0.0.0: undefined symbol: _ZN7QwtPlot16staticMetaObjectE
>>>

Conclusion: There is a problem with my qtgui install but I don't know how to debug any further to apply a fix. I've googled the traceback output with no luck. I'm hoping someone has come across and fixed this issue before who could explain what's going on.

v/r,
Rich

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