Conflict between dynamic linking priority in OSX?

问题

There is a dynamic-linking-conflict between different libjpeg dynamic libraries on OSX. First there is a standard native libJPEG.dylib (in /System/Library/Frameworks/ImageIO.framework/Versions/A/Resources/). But if you are using MacPorts, you can also have a port-related libjpeg.dylib in (in /opt/local/lib). The latter may for example have been installed as a dependency for some other port.

This creates a problem when you link against your system libJPEG (which is preferred). Then if /opt/local/lib is in DYLD_LIBRARY_PATH, that path will be prioritised when searching for a dynamic lib, resulting in a runtime error when loading symbols:

dyld: Symbol not found: __cg_jpeg_resync_to_restart
 Referenced from:
/System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
 Expected in: /opt/local/lib/libJPEG.dylib
in /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
Trace/BPT trap: 5

So I have two questions (likely related):

What is a good way of solving the actual problem (removing /opt/local/lib from DYLD_LIBRARY_PATH obviously solves it but creates problems for other dependencies)?
What other paths are searched for dynamic libs (I.e. Where is the \"/System/Library\" path specified) and why does DYLD_LIBRARY_PATH rank higher priority-wise?

回答1:

You should not set library paths using DYLD_LIBRARY_PATH. As you've discovered, that tends to explode. Executables and libraries should have their library requirements built into them at link time. Use otool -L to find out what the file is looking for:

$ otool -L /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
/System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO:
    /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO (compatibility version 1.0.0, current version 1.0.0)
    ...
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)

For an example of one of my homebrew-built programs:

$ otool -L /usr/local/bin/gifcolor
/usr/local/bin/gifcolor:
    /usr/local/Cellar/giflib/4.1.6/lib/libgif.4.dylib (compatibility version 6.0.0, current version 6.6.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 159.1.0)

Note that it references /usr/local. If you've built it in such a way that it references the wrong library, I recommend rebuilding and pointing it to the correctly library.

If that's impossible, it is possible to edit what path is used using install_name_tool, but there are cases where this doesn't work, such as if the new path is longer than the old path and you didn't link it with -header_pad_max_install_names. Rebuilding with the correct path is preferred.

Note that there are a few "special" paths available that allow libraries to be found relative to their loader. See @executable_path/ and its kin in the dyld(1) man page.

回答2:

I experienced similar problem while using OpenCV in MacOS El Capitan. Solved the problem using the solution in the link

Solution is to delete some dlylibs in the /usr/local/lib directory and create symbolic links to related files /System/Library/Frameworks/ImageIO.framework/Resources/

cd /usr/local/lib
rm libgif.dylib
ln -s /System/Library/Frameworks/ImageIO.framework/Resources/libGIF.dylib libGIF.dylib
rm libjpeg.dylib
ln -s /System/Library/Frameworks/ImageIO.framework/Resources/libJPEG.dylib libJPEG.dylib
rm libtiff.dylib
ln -s /System/Library/Frameworks/ImageIO.framework/Resources/libTIFF.dylib libTIFF.dylib
rm libpng.dylib
ln -s /System/Library/Frameworks/ImageIO.framework/Resources/libPng.dylib libPng.dylib

回答3:

I had a similar error when trying to run Apache Celix on macOS Sierra If you use Homebrew to install libjpeg, libtiff, libpng which may confuse the linker to use macOS imageIO library. Simple fix is unlink those libs:

brew unlink libpng
brew unlink libtiff
brew unlink libjpeg

Re-link those libs whenever we need to:

brew link libpng
brew link libtiff
brew link libjpeg

回答4:

If using Qt Creator, you have to uncheck the Add build library search path to DYLD_LIBRARY_PATH and DYLD_FRAMEWORK_PATH option from the Run section in the Projects tab:

回答5:

I had a similar error, and i solved putting the following variable in my bash_profile:

export DYLD_LIBRARY_PATH=/usr/lib/:$DYLD_LIBRARY_PATH

回答6:

I followed the instructions mdemirst suggested and it fixed my issue. I am using OS X Sierra.

I created a gist just in case someone else runs into the same issue.

Gist to fix Spidermonkey errors

来源：https://stackoverflow.com/questions/17643509/conflict-between-dynamic-linking-priority-in-osx

标签

c++

macos

macports

dylib