Re: Python errors running flowgraph - first attempt

Hello:

Just chiming in with the fact that I am struggling with this identical
issue using a “Dizzy” build for an Ettus E310 running on the device.

I have tried a number of different example flowgraphs that utilize QT
GUI
and have come up with the exact same error

File "/usr/lib/pyhon2.7/site-packages/PyQt4/Qt.py, line 3, in
from
pyQt4.QTDeclarativeImport *
ImportError : /usr/lib/python2.7/site-packages/PyQt4/QtDEclarative.so:
undefined symbol: _ZTI16QTDeclarativeView

Any insights are always welcomed.

On Sun, Feb 8, 2015 at 2:17 PM, Larry Van Der J. [email protected]
wrote:

ImportError : /usr/lib/python2.7/site-packages/PyQt4/QtDEclarative.so:
undefined symbol: _ZTI16QTDeclarativeView

Any insights are always welcomed.

I’ve done some further investigating on this issue, though I do not
know it’s root cause. I worked around the issue by loading the
library(s) containing the missing symbols using LD_PRELOAD. It might
be because you simply don’t have the package containing
QTDeclarativeView installed. It comes from the QtDeclarative module
of Qt, and you should have a library named something like:
“libQtDeclarative.so*”

You can find those symbols using readelf on your system. If you are
on an embedded system, you’ll need to use your embedded version of
readelf:

$ readelf -s /usr/lib64/libQtDeclarative.so.4.8.5 (change names/paths
to match your system)

In my case, I have the modules but my python app is not finding them.
Much more work ahead of me! :wink:

Regards,

Chris

Sorry that I have no insight into this right now, but I wanted to follow
up
and see if there was any progress made on this problem?

Tom

On Mon, Feb 9, 2015 at 11:28 AM, Larry Van Der J. [email protected]

Hi …

If you run GRC on the E310 with:

LD_PRELOAD="/usr/lib/libQtDeclarative.so.4.8.6
/usr/lib/libQtSvg.so.4.8.6
/usr/lib/libQtXml.so.4.8.6 /usr/lib/libQtWebKit.so.4.9.4"
gnuradio-companion

You are able to get to the point where the problem is an unavailablity
of
PYQty4.Qwt5 as Qwt
ImportError: no module named Qwt5 …

As we speak I am trying to examine if I can cross compile The missing
module and install it on the target device to get things to proceed
further.

Thanks for your interest.

LVDJ

Thanks:

The info Chris sent along has helped to move this along although at this
point I still don’t have a solution or a root cause.

The library that issues the error message is
/usr/lib/python2.7/site-packages/PyQt4/QtDeclarative.so and the symbol
it
complains about is _ZTI16QDeclarativeView

When you Readelf this file you find:

Dynamic section at offset 0x40728 contains 29 entries:
Tag Type Name/Value
0x00000001 (NEEDED) Shared library: [libQtGui.so.4]
0x00000001 (NEEDED) Shared library:
[libQtCore.so.4]
0x00000001 (NEEDED) Shared library:
[libstdc++.so.6]
0x00000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x00000001 (NEEDED) Shared library: [libc.so.6]
0x0000000e (SONAME) Library soname:
[libQtDeclarative.so.1]

and

00040128 0000b202 R_ARM_ABS32 00000000 _ZTI16QDeclarativeView

and

178: 00000000 0 NOTYPE GLOBAL DEFAULT UND
_ZTI16QDeclarativeView

There is also a library in /usr/lib that is libQtDeclarative.so.4.8.6
that
has symbolic links to it named libQtDeclarative.so, .so.4 and .so.4.8.
I
though that if I added one for libQtDeclarative.so.1 this might fix the
issue, but it did not.

When you readelf libQtDeclarative.so.4.8.6 you find:

Dynamic section at offset 0x2ce040 contains 34 entries:
Tag Type Name/Value
0x00000001 (NEEDED) Shared library:
[libQtScript.so.4]
0x00000001 (NEEDED) Shared library: [libQtSql.so.4]
0x00000001 (NEEDED) Shared library:
[libQtXmlPatterns.so.4]
0x00000001 (NEEDED) Shared library: [libQtGui.so.4]
0x00000001 (NEEDED) Shared library:
[libQtNetwork.so.4]
0x00000001 (NEEDED) Shared library: [libQtCore.so.4]
0x00000001 (NEEDED) Shared library: [libstdc++.so.6]
0x00000001 (NEEDED) Shared library: [libm.so.6]
0x00000001 (NEEDED) Shared library: [libgcc_s.so.1]
0x00000001 (NEEDED) Shared library: [libc.so.6]
0x0000000e (SONAME) Library soname:
[libQtDeclarative.so.4]

and

002d0c94 0009ef02 R_ARM_ABS32 002d0c80 _ZTI16QDeclarativeView
002d0d8c 0009ef02 R_ARM_ABS32 002d0c80 _ZTI16QDeclarativeView

and

2543: 002d0c80 12 OBJECT GLOBAL DEFAULT 20 _ZTI16QDeclarativeView

I also tried copying /usr/lib/libQtDeclarative.so.4.8.6 to the
/usr/lib/python2.7/site-packages/pyQt4 directory as
libQtDeclarative.so.1
to no avail.

I tried calling gnuradio-companion with
LD_PRELOAD=/usr/lib/libQtDeclarative.so.4.8.6
gnuradio-companion and this let the process proceed a little further
this
time the undefined symbol is in line 11 of QT.py in QTSvg.so and is
_ZTI10QSvgWidget.

I will keep drilling down on this, but thought I might post first just
in
case someone recognizes the real issue and perhaps it can be fixed with
a
simple adjustment to the environment.

With respect to the concept that GRC is not really something to run on
the
embedded processor, that’s surely valid, but unless I do not understand
how
these pieces work, if the QT GUI can run you can’t get graphical
elements
to work even in the produced Python code and that seriously reduces the
utility of the embedded device.

All comments and direction are appreciated.

LVDJ

I never had time to make progress on Qwt so I just removed the Qwt
widgets from my flow graph and used other ones. Hoping to find time
this week to work on a PyQwt recipe for OE, not sure what other things
on my schedule might thwart those plans :wink:

No guarantees that even if I manage to get Qwt built, it won’t have
runtime issues. I’m a python newbie, too!

I built a dizzy-based image and I now have gqrx and my FM broadcast
tutorial running on my embedded x86_64 target. Need to find time to
make more progress on the project soon!

-Chris

On Fri, Feb 27, 2015 at 12:11 PM, Tom R. [email protected] wrote:

Tag Type Name/Value
00040128 0000b202 R_ARM_ABS32 00000000 _ZTI16QDeclarativeView
When you readelf libQtDeclarative.so.4.8.6 you find:
0x00000001 (NEEDED) Shared library: [libQtCore.so.4]
002d0d8c 0009ef02 R_ARM_ABS32 002d0c80 _ZTI16QDeclarativeView
LD_PRELOAD=/usr/lib/libQtDeclarative.so.4.8.6 gnuradio-companion and this
work even in the produced Python code and that seriously reduces the utility


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