undefined reference to 'std:: .... ' in libQt5WebEngineCore.so

[Ricky9902]

Hi!
I'm updating a large project from 4.8.6 to 5.6.3 on Ubuntu 18.04.1 and I encountered one problem.

undefined reference to 'std::_throw_out_of_range_fmt(char const, ....)@Qt_5'
undefined reference to 'std::_throw_bad_function_call()@Qt_5'
collect2:error: ld returned 1 exit status
in a file libQt5WebEngineCore.so

I've run out of ideas on how to solve it.

[Christian Ehrlicher]

How did you install the Qt version?
You've most likely an to old libstdc++ version on your system - std::throw_out_of_range(const char*) was added with c++11: https://en.cppreference.com/w/cpp/error/out_of_range

[JoeCFD]

add
set(CMAKE_CXX_STANDARD 11)
in cmake file
and
CONFIG += c++11
in pro file

17 will work as well.

[Ricky9902]

Thank you for your replies

@Christian-Ehrlicher
I downloaded Qt from the 5.6.3 arhcives, download.qt.io. I checked and I have the highest version of libstdc++ available for ubuntu 18.04.

@JoeCFD
I tried it, but the error is still the same. By cmake do you mean the qt5config.cmake?

I already had CONFIG += C++11 and QMAKE_CXXFLAGS += -std=c++11 included in my .pro file.
In compile output I can see that g++ is called with -std=c++11

[JonB]

@Ricky9902
What version of gcc and what version of libstdc++.so do you actually have? Try Googling std::__throw_out_of_range_fmt, e.g. https://github.com/BVLC/caffe/issues/4973 ?

[Ricky9902]

@JonB
gcc/g++ is 7.5.0
libstdc++6 is 8.4.0 (libstdc++.so.6.0.25)
I followed the advice from the thread you shared and (most likely due to my mistake) it somehow broke my virtual machine.

Edit:
Links seem fine

[JoeCFD]

@Ricky9902 forget cmake if you use pro file.

[Ricky9902]

Creating new virtual Ubuntu and reinstalling all the packages and Qt seems to have solved the problem.
I belive that I destroyed some links between few files or just overwritten few .so files when I was trying to manually solve this problem.
Thank you for your replies!