Missing symbol in mex .mexa in Simulink

Hi to all.

I have created a .mexa with mex function. It compiles well. Now I want to use this .mexa in simulink (with S-function).

But when I run simulink it gives me these errors:

Missing symbol '_ZNKSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEE7compareEPKc' required by 'positionXY.mexa64'
Missing symbol '_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC1EPKcRKS3_' required by 'positionXY.mexa64'
Missing symbol '_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEC1ERKS4_' required by 'positionXY.mexa64'
Missing symbol '_ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED1Ev' required by 'positionXY.mexa64'.

How can I solve this? I am working with matlab 2017a. In previous version of Matlab this .mexa works...

Thanks a lot.

[Walter Roberson]

Missing symbol 'std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::compare(char const*) const' required by 'positionXY.mexa64'
Missing symbol 'std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&)' required by 'positionXY.mexa64'
Missing symbol 'std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)' required by 'positionXY.mexa64'
Missing symbol 'std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()' required by 'positionXY.mexa64'.

Those appear to be routines I would expect to see in the standard C++ library, libC++

[Álvaro Salcedo]

I have fixed!!!

Just add this in bashrc:

export LD_PRELOAD=$LD_PRELOAD:/usr/lib/x86_64-linux-gnu/libstdc++.so.6:/usr/lib/x86_64-linux-gnu/libprotobuf.so.9

And then do this in terminal

source ./bashrc