Linking error in linux

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I'm a new user in ubuntu 14.04 32 bit to do my leddar project.I have also installed all necessary packages (Qt, other libraries) but there are many linking errors when I catkin_make everything. And until to now I'm facing some linking problem and don't how to solve it.

follow is the error shows to me:

/home/darwin/catkin_ws/src/leddar/lib/libLeddar.so: undefined reference to `QString::toLocal8Bit_helper(QChar const*, int)'
/home/darwin/catkin_ws/src/leddar/lib/libLeddarC.so: undefined reference to `QString::toUtf8_helper(QString const&)'
collect2: error: ld returned 1 exit status
make[2]: *** [/home/darwin/catkin_ws/devel/lib/leddartech/leddartech_node] Error 1
make[1]: *** [leddar/CMakeFiles/leddartech_node.dir/all] Error 2
make: *** [all] Error 2
Invoking "make -j4 -l4" failed

Got anyone meet this kind of problem before and share your solving way? Thank you!

What I have tried:

this is the website i usd to download the leddar package:https://github.com/jpmerc/leddartech

Posted 23-Mar-16 23:51pm

Zero_J

Updated 22-Jun-16 5:40am

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Jochen Arndt 24-Mar-16 6:20am

I had a look at the LeddarTech GitHub page. There are only pre-build libraries and no sources to build them yourself. So only they can help you.

But it is curious that the libraries reference Qt library functions. They seem to be just hardware access libraries and should not be linked with any other non default libraries (especially 3rd party ones like Qt).

Zero_J 25-Mar-16 0:25am

Yes,it is.I had try many way to solve it. And every time will come out new problem but these problem all relate to the libraries.

3 solutions

Solution 4

Hello!

I know it is late, but I've got exactly the same problem and solved it a little bit the other way.

The problem was in version of Qt - 5.2.0.
You shoul uninstall the previos Qt by the most hardest way (i am by myself not good in linux, i used this )[^].

And then installed qt-opensource-linux-x64-5.4.0.run from
[^]

That is all in general. After that there was several easy problems with symlink, which were repaired easily.

I spent on that problem a whole day, hope that helps one day))

Posted 22-Jun-16 5:40am

Mikaell

Solution 1

You are missing a library reference in your linker section. Check the documentation for QString::toLocal8Bit_helper and QString::toUtf8_helper to see which one is required.

Posted 23-Mar-16 23:59pm

Richard MacCutchan

Comments

Zero_J 24-Mar-16 6:13am

Thank you for replying but the problem is that I cannot find them. "/home/darwin/catkin_ws/src/leddar/lib/libLeddar.so " because the lib file there don't have them. By the way, those lib is pre-compile file so I cannot ope to check them

Richard MacCutchan 24-Mar-16 7:26am

It is the Qt library that is missing, or some derivation of Qt that includes these two methods. You could try asking the people at Leddartech for help.

Zero_J 25-Mar-16 0:22am

Thank you, I will try ask them for more help.

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Zero_J · Accepted Answer · 2016-04-01T16:53:00

Solution 3

I had solve my problem. I just reinstall my linux system to 64bit then download these Leddar SDK package and Leddar ROS package and Qt5 then everything was fine! I believe there have some of the package was not reliable in 32bit system so cause so many problem.

And thank you for everyone's help!

Posted 1-Apr-16 16:53pm

Zero_J

Comments

Albert Holguin 8-Apr-16 19:44pm

It's possible that it wasn't finding the Qt libraries in the expected location. You could have actually specified the location by either editing the makefile or by using a load library path (environment variable).