# Re: Python errors running flowgraph - first attempt **URL:** \ **Category:** GNU Radio\ **Created:** [February 8, 2015, 8:18pm UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126 "2015-02-08T20:18:16Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![addis\_a](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/c4cdca/32.png) [@addis\_a](https://www.ruby-forum.com/u/addis_a)\ **Post date:** [February 8, 2015, 8:18pm UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126/1 "2015-02-08T20:18:16Z")
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. ---
**Author:** ![larryj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/e480ec/32.png) [@larryj](https://www.ruby-forum.com/u/larryj)\ **Post date:** [February 9, 2015, 11:01am UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126/2 "2015-02-09T11:01:30Z")
On Sun, Feb 8, 2015 at 2:17 PM, Larry Van Der J. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) 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! 😉 Regards, Chris ---
**Author:** ![larryj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/e480ec/32.png) [@larryj](https://www.ruby-forum.com/u/larryj)\ **Post date:** [February 27, 2015, 6:13pm UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126/3 "2015-02-27T18:13:20Z")
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. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) ---
**Author:** ![larryj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/e480ec/32.png) [@larryj](https://www.ruby-forum.com/u/larryj)\ **Post date:** [February 27, 2015, 9:08pm UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126/4 "2015-02-27T21:08:24Z")
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 ---
**Author:** ![larryj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/e480ec/32.png) [@larryj](https://www.ruby-forum.com/u/larryj)\ **Post date:** [February 9, 2015, 5:30pm UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126/5 "2015-02-09T17:30:04Z")
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 ---
**Author:** ![larryj](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/e480ec/32.png) [@larryj](https://www.ruby-forum.com/u/larryj)\ **Post date:** [March 1, 2015, 4:15pm UTC](https://www.ruby-forum.com/t/re-python-errors-running-flowgraph-first-attempt/234126/6 "2015-03-01T16:15:03Z")
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 😉 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. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) 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 > > > > * * * > > > > Discuss-gnuradio mailing list > > [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) > > [Discuss-gnuradio Info Page](https://lists.gnu.org/mailman/listinfo/discuss-gnuradio) – Life is like Linux - it never stands still.