Qt fails in GNOME/Fedora 22 #368

janpipek opened this Issue Jun 29, 2015 · 17 comments


None yet

I have Fedora 22, Anaconda 2.2.0, Python 2.7.10, pyqt 4.11.3 (all packages updated today). The same with python 3.4..

When KDE is running, everything works fine.
But once GNOME is started, any attempt to start application using PyQt (my own applications, spyder, ipython qtconsole) fails with the following message:

/home/honza/anaconda/bin/python: symbol lookup error: /lib64/libpangoft2-1.0.so.0: undefined symbol: FcWeightFromOpenType

Thanks for any ideas, luckily I use Gnome only occasionally ;-)

@janpipek janpipek referenced this issue in janpipek/hlava Jun 29, 2015

Fails to start in GNOME #10


Please run

conda install -c asmeurer pango

to fix this problem. It only occurs in Fedora because it's the only major distribution to be using a too recent version of fontconfig.


Thanks a lot. It really works.


Thanks It works with Fedora 22 for spyder too

daudich commented Oct 13, 2015

Fedora 22 👍




Legend! Thank you very much.


Worked like a charm!


Worked Perfectly!
I was the same trouble with matplotlib on Fedora 22. Thanks a lot!


Works now in Python 3.5 in condas and Fedora 22. Such Joy. Many thanks.


i got this error

/lib64/libpangoft2-1.0.so.0: undefined symbol: FcWeightToOpenType

i fixed this problem by your solution

$ conda install -c asmeurer pango

but i got another error:

/home/niranjan/anaconda3/bin/../lib/libgomp.so.1: version `GOMP_4.0' not found (required by /home/niranjan/mxnet/python/mxnet/../../lib/libmxnet.so)

can you tell me how to fix this problem.thanks in advance.


Do you have the libgcc package installed?


yes, it is installed


What program are you trying to run? I see the error comes from libmxnet.so but I haven't heard of that library before.


deep learning package https://mxnet.readthedocs.org/en/latest/build.html#python-package-installation
can you tell me any working solution for this problem.thanks in advance


No idea, sorry. Your problem is not related to the problem on this issue (which you confirmed was solved after following my advice).

havocp commented Jan 25, 2016

I think the problem is that Fedora has a Pango that requires latest fontconfig, and my conda env has an older fontconfig than the system one:

(py3)[hp@localhost anaconda-ui]$ nm -D /lib64/libfontconfig.so.1 | grep FcWeightFromOpenType
00000033faa21dd0 T FcWeightFromOpenType
(py3)[hp@localhost anaconda-ui]$ nm -D ~/bin/Anaconda-2.2.0/envs/py3/lib/libfontconfig.so.1 | grep FcWeightFromOpenType
(py3)[hp@localhost anaconda-ui]$

Conda has fontconfig 2.11.1, this function was added in 2.11.91. Fedora 22 has 2.11.94.

conda's older fontconfig is breaking the system pango, essentially. So installing a conda version of pango would fix it as discussed here, as would putting a newer fontconfig in conda.

This will presumably break on other linux distributions if/when they upgrade Pango.

The danger in installing a conda version of pango is that presumably that's also a downgrade in version from the system pango, and apps higher in the stack could rely on whatever is new in Pango.


want to confirm that

conda install -c asmeurer pango

also fixes the

~/anaconda3/bin/python: symbol lookup error: /usr/lib/libpangoft2-1.0.so.0: undefined symbol: FcWeightFromOpenType

error in Arch Linux

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment