Dylib ok at link time but not at runtime - macos

Question

I have a problem linking correctly my project. The project is built with CMAKE. Linking seems fine, but at run time an error is thrown.
Here is the command that was used for linking:
$ /usr/bin/clang -Wl,-search_paths_first -Wl,-headerpad_max_install_names \
CMakeFiles/project.dir/src/conf.c.o CMakeFiles/project.dir/src/tun-compat.c.o \
CMakeFiles/project.dir/src/compress.c.o CMakeFiles/project.dir/src/mc.c.o \
CMakeFiles/project.dir/src/hexdump.c.o CMakeFiles/project.dir/src/server.c.o \
CMakeFiles/project.dir/sys/unix/log.c.o CMakeFiles/project.dir/sys/unix/imsg.c.o \
CMakeFiles/project.dir/ sys/unix/imsg-buffer.c.o CMakeFiles/project.dir/sys/unix/toto.c.o \
CMakeFiles/project.dir/sys/unix/toto.c.o CMakeFiles/project.dir/sys/unix/util.c.o \
CMakeFiles/project.dir/sys/unix/conf.c.o CMakeFiles/project.dir/sys/unix/tntsocket.c.o \
-o bin/project/opt/local/lib/libevent_openssl.dylib /opt/local/lib/libevent_core.dylib \
/usr/lib/libz.dylib /opt/local/lib/libyajl.dylib /opt/local/lib/libtapcfg.dylib
The error I get:
$ ./bin/project
dyld: Library not loaded: build/libtapcfg.dylib
Referenced from: /Users/Antoine/project/./bin/project
Reason: image not found
zsh: trace trap ./bin/project
Additional infos:
$ dyldinfo -dylibs bin/projectattributes
dependent dylibs
/opt/local/lib/libevent_openssl-2.0.5.dylib
/opt/local/lib/libevent_core-2.0.5.dylib
/usr/lib/libz.1.dylib
/opt/local/lib/libyajl.2.dylib
build/libtapcfg.dylib
/usr/lib/libSystem.B.dylib
It looks like black magic to me. The linker is able to find the symbols, but end up by changing the path of the library even if I can't see any difference in the way it is handled in the linking command...
The lib location is /opt/local/lib/libtapcfg.dylib
$ ls -lhF /opt/local/lib/libtapcfg.dylib
-rwxr-xr-x 1 root admin 20K 14 jui 18:05 /opt/local/lib/libtapcfg.dylib*
Does the problem maybe come from the lib I am linking to?

Answer 1

The issue is with how you built and installed libtapcfg.
You seem to have copied it from your local directory to /opt/local/lib and thus its file system path does not match what is stored in the library.
Either leave the lib in your local path or when building it tell the linker where it will end up or copy to /usr/local/lib which is hard coded in the linker. See Apple developer's note on dynamic libraries
You should only put things in /opt/local when using macports by means of a port. In this case create a local portfile which does not have to do much and macports standard work will put the correct information in the library to make it work from /opt/local/lib