Set LD_LIBRARY_PATH correctly

boostenvironment-variableslibrariesMATLAB

I am using Docker with image of Ubuntu 16.04. I am using this docker to run:

  • Import C++ classes in python with the help of boost.python
  • Import matlab's python package in python with the help Matlab Runtime (MCR).

Before I have installed MCR in the docker, I have installed boost using:

$ sudo apt-get install -y libboost-all-dev

and I was able to wrap C++ classes and call them in python. Then I have installed MCR and one of the requirement is to set LD_LIBRARY_PATH to Matlab's library. 

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/MATLAB/MATLAB_Runtime/v94/runtime/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/bin/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/extern/bin/glnxa64

It worked, I was able to run matlab's python package in python but testing the C++ classes wrappers failed due to change of LD_LIBRARY_PATH. For example, I get the following error when I try to import C++ class in python:

 /usr/lib/x86_64-linux-gnu/libpython3.4m.so.1.0: undefined symbol: XML_SetHashSalt

If I unset LD_LIBRARY_PATH C++ import works but MCR fails. So the question what LD_LIBRARY_PATH should be in order to run both C++ classes and Matlab's python package successfully?

I have tried to add path to boost libraries to LD_LIBRARY_PATH but didn't work, so the env value would be:

/usr/lib/x86_64-linux-gnu:/usr/local/MATLAB/MATLAB_Runtime/v94/runtime/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/bin/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/extern/bin/glnxa64

EDIT

the dependencies of C++ library file before setting the LD_LIBRARY_PATH:

    linux-vdso.so.1 (0x00007ffcee0dc000)
    libpython3.4m.so.1.0 => /usr/lib/x86_64-linux-gnu/libpython3.4m.so.1.0 (0x00007f9d69e59000)
    libboost_python-py34.so.1.55.0 => /usr/lib/x86_64-linux-gnu/libboost_python-py34.so.1.55.0 (0x00007f9d69c09000)
    libstdc++.so.6 => /usr/lib/x86_64-linux-gnu/libstdc++.so.6 (0x00007f9d698fe000)
    libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f9d695fd000)
    libgcc_s.so.1 => /lib/x86_64-linux-gnu/libgcc_s.so.1 (0x00007f9d693e7000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f9d6903c000)
    librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f9d68e34000)
    libexpat.so.1 => /lib/x86_64-linux-gnu/libexpat.so.1 (0x00007f9d68c0b000)
    libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007f9d689f0000)
    libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f9d687d3000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007f9d685cf000)
    libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007f9d683cc000)
    /lib64/ld-linux-x86-64.so.2 (0x00007f9d6a6c3000)

After setting the LD_LIBRARY_PATH:

    linux-vdso.so.1 (0x00007ffc42e9b000)
    libpython3.4m.so.1.0 => /usr/lib/x86_64-linux-gnu/libpython3.4m.so.1.0 (0x00007fad9635b000)
    libboost_python-py34.so.1.55.0 => /usr/lib/x86_64-linux-gnu/libboost_python-py34.so.1.55.0 (0x00007fad9610b000)
    libstdc++.so.6 => /usr/local/MATLAB/MATLAB_Runtime/v94/sys/os/glnxa64/libstdc++.so.6 (0x00007fad95d8a000)
    libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fad95a89000)
    libgcc_s.so.1 => /usr/local/MATLAB/MATLAB_Runtime/v94/sys/os/glnxa64/libgcc_s.so.1 (0x00007fad95873000)
    libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fad954c8000)
    librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007fad952c0000)
    libexpat.so.1 => /usr/local/MATLAB/MATLAB_Runtime/v94/bin/glnxa64/libexpat.so.1 (0x00007fad95095000)
    libz.so.1 => /lib/x86_64-linux-gnu/libz.so.1 (0x00007fad94e7a000)
    libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007fad94c5d000)
    libdl.so.2 => /lib/x86_64-linux-gnu/libdl.so.2 (0x00007fad94a59000)
    libutil.so.1 => /lib/x86_64-linux-gnu/libutil.so.1 (0x00007fad94856000)
    /lib64/ld-linux-x86-64.so.2 (0x00007fad96bc5000)

Best Answer

You have a couple of options:

  1. Prefix the path to your shared libraries in the export statement above (more than likely $LD_LIBRARY_PATH is not set on your system and so the only paths that are getting set are the ones explicitly set in your export statement.)

     export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib/:/usr/lib/:/usr/lib64/:/usr/local/MATLAB/MATLAB_Runtime/v94/runtime/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/bin/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/sys/os/glnxa64:/usr/local/MATLAB/MATLAB_Runtime/v94/extern/bin/glnxa64

    This export statement will not be a permanent part of your shell sessions unless you add it to .bashrc fyi.

  2. Add the MATLAB library path to /etc/ld.so.conf.d/ and run ldconfig to identify the new paths for the linker on your system.

    (BTW I am guessing at the MATLAB library name. You might need to make the name of the file something other than MATLAB like all lower case or something else. Basically we need the name of the library as it is referenced during the linking process. You could inspect a make file to see how this is referenced.)

     # Add the file '/etc/ld.so.conf.d/MATLAB' with the following lines 
 /usr/local/MATLAB/MATLAB_Runtime/v94/runtime/glnxa64
 /usr/local/MATLAB/MATLAB_Runtime/v94/bin/glnxa64
 /usr/local/MATLAB/MATLAB_Runtime/v94/sys/os/glnxa64
 /usr/local/MATLAB/MATLAB_Runtime/v94/extern/bin/glnxa64

    Then run ldconfig.

     sudo ldconfig

    You may need to unset the $LD_LIBRARY_PATH variable to make the linker use the normal system search path and pickup the new search path for MATLAB.

     unset LD_LIBRARY_PATH
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