c++ - Conflict between dynamic linking priority in OSX? -

there dynamic-linking-conflict between different libjpeg dynamic libraries on osx. first there standard native libjpeg.dylib (in /system/library/frameworks/imageio.framework/versions/a/resources/). if using macports, can have port-related libjpeg.dylib in (in /opt/local/lib). latter may example have been installed dependency other port.

this creates problem when link against system libjpeg (which preferred). if /opt/local/lib in dyld_library_path, path prioritised when searching dynamic lib, resulting in 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 have 2 questions (likely related):

1. what way of solving actual problem (removing /opt/local/lib dyld_library_path solves creates problems other dependencies)?

2. what other paths searched dynamic libs (i.e. "/system/library" path specified) , why dyld_library_path rank higher priority-wise?

you should not set library paths using dyld_library_path. you've discovered, tends explode. executables , libraries should have library requirements built them @ link time. use otool -l find out file 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 example of 1 of 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 references /usr/local. if you've built in such way references wrong library, recommend rebuilding , pointing correctly library.

if that's impossible, possible edit path used using install_name_tool, there cases doesn't work, such if new path longer old path , didn't link -header_pad_max_install_names. rebuilding correct path preferred.

note there few "special" paths available allow libraries found relative loader. see @executable_path/ , kin in dyld(1) man page.