Home/ Questions/Q 500311
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-05-13T06:04:27+00:00

I am linking a (Python extension) library that embeds the Matlab engine with the

  • 0

I am linking a (Python extension) library that embeds the Matlab engine with the following command (generated using cmake)

c++ -mmacosx-version-min=10.6 -bundle -headerpad_max_install_names  -o library.so library.o /Applications/MATLAB_R2009b.app/bin/maci64/libeng.dylib /Applications/MATLAB_R2009b.app/bin/maci64/libmx.dylib -framework Python

resulting in 

$ otool -L library.so
library.so:
    @loader_path/libeng.dylib (compatibility version 0.0.0, current version 0.0.0)
    @loader_path/libmx.dylib (compatibility version 0.0.0, current version 0.0.0)
    /System/Library/Frameworks/Python.framework/Versions/2.6/Python (compatibility version 2.6.0, current version 2.6.1)
    /opt/local/lib/gcc44/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.13.0)
    /opt/local/lib/gcc44/libgcc_s.1.dylib (compatibility version 1.0.0, current version 1.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.0.0)

However, when I try to use the library, I get an error message:

ImportError: dlopen(./library.so, 2): Library not loaded: @loader_path/libmex.dylib
  Referenced from: ./library.so
  Reason: image not found

I believe the problem stems from the fact that the linker includes the matlab dylib files in the form @loader_path/libeng.dylib rather than using the full path, even though I give the full path to g++. How can I force the linker to use the full path?

I know one solution is to use 

export DYLD_LIBRARY_PATH=/Applications/MATLAB_R2009b.app/bin/maci64:$DYLD_LIBRARY_PATH

which is where those library files reside, but I’d like to avoid that as it causes some other problems.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    Manually changing the files using install_name_tool

    install_name_tool -change "@loader_path/libeng.dylib" "/Applications/MATLAB_R2009b.app/bin/maci64/libeng.dylib" library.so 
install_name_tool -change "@loader_path/libmx.dylib" "/Applications/MATLAB_R2009b.app/bin/maci64/libmx.dylib" library.so

    I could use this as a temporary fix, but I wonder if there isn’t a better solution where the linker is given a setting to use the full paths.

    • 0