Issue with installation on Ubuntu 13.04 about openbr

[jklontz]

Thanks for the very detailed error report, unfortunately this error is just
as peculiar to me as it is to you. The best I can suggest is to fire up a
clean Ubuntu VM, confirm br runs correctly, then start working backwards to
figure out how your current environment differs. The fact that it's still
entering a Qt4 library is a huge red flag, we don't use Qt4 at all.
Best of luck,
Josh

On Thu, Aug 15, 2013 at 3:18 PM, shashank singh [email protected]:

Hey guys,
Thanks for the great work. This library would really help me with my
occasional hobby projects. I already have some cool stuff in my head which
I will start churning out once it this puzzling issue is solved.
Issue :

So, I have a Ubuntu 13.04[1] machine and my every time I compile openbr,
it compiles fine but while executing it crashes with Segmentation fault[4].

How To reproduce :

Well executing br , alone did it :)

On further investigation I found out that although openbr cmake was
loading header files from qt5 it was linking to qt4 libraries [2][3][5][6].

I have been literally hitting my head on this issue for past 2 days, any
help would be pretty cool.
References : [1] OS Version

:~/code/openbr/build$ lsb_release -a
Distributor ID: Ubuntu
Description: Ubuntu 13.04
[2] Qt5 Version

I have compiled my own Qt5
~/code/openbr/build$ qmake --version
QMake version 3.0
Using Qt version 5.0.2 in /usr/lib/i386-linux-gnu
[3] Qt4 Version

This is stock qt4 that comes with Ubuntu
~/code/openbr/app$ qmake-qt4 --version
QMake version 2.01a
Using Qt version 4.8.4 in /usr/lib/i386-linux-gnu
[4] Crash dump

(gdb) bt
~/code/openbr/app/br$ gdb br
0. 0xb369f5e2 in ?? () from /usr/lib/i386-linux-gnu/ libQtTest.so.4

1. 0xb7fed216 in ?? () from /lib/ld-linux.so.2
2. 0xb7fed2fc in ?? () from /lib/ld-linux.so.2
3. 0xb7fdf1df in ?? () from /lib/ld-linux.so.2
   [5] Cmake setup

[image: cmake_setup_screenshot from 2013-08-16 00 32 19]https://f.cloud.github.com/assets/60755/970850/7bc98f4a-05dd-11e3-994c-816767ebcdeb.png
[6] Crash GDB bt

[image: crash_screenshot from 2013-08-16 00 37 23]https://f.cloud.github.com/assets/60755/970871/004c9028-05de-11e3-8807-2e6849440590.png

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/94
.

[shashanksingh]

Thanks man, will try using a VM . I am guessing its just not my day , even Docker is not working out for me https://www.docker.io/

[shashanksingh]

Hey,
Yeah I guess something is competetly off in my ubuntu installation. I did strace on openbr executable and this is what i found

open("/home/developer/code/qt5/qtbase/lib/ libQt5Gui.so.5 ", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/i386-linux-gnu/ libQtTest.so.4 ", O_RDONLY|O_CLOEXEC) = 3

for some reason it hell bent on using test library from qt4, hence the crash. Now only if I could figure out why :)

[smvv]

For future readers: check that your OpenCV library is linked with Qt5 instead of Qt4.

To check, use: ldd /path/to/libopencv.so | grep -i qt

If there is a library ending with "libQtTest.so.4", you have to rebuild OpenCV with -DWITH_QT5=ON. Note that if you pass -DWITH_QT=ON to cmake, OpenCV will use Qt4 instead of Qt5.

[shashanksingh]

thanks @smvv :)