Jim, loading a specific version of a shared library requires two things:
a. Use absolute path to the library in the cffi lib spec b. Make sure the dependencies (see output of otool -L ) (the paths to the dependencies) are at the beginning of the paths set in the environment variable DYLD_LIBRARY_PATH. Best Frank -- Frank Gönninger DG1SBG Consequor Consulting AG > Am 20.09.2016 um 16:46 schrieb Jim Newton <jimka.i...@gmail.com>: > > Hi Frank, thanks for the information. If you always use /usr/local/lib then > what do you do when you need to run two different independent applications > which have different requirements? > >> On Tue, Sep 20, 2016 at 3:44 PM, Frank Goenninger <f...@me.com> wrote: >> Am 20.09.2016 um 15:32 schrieb Luís Oliveira <luis...@gmail.com>: >> > >> > On Tue, Sep 20, 2016 at 10:53 AM, Jim Newton <jimka.i...@gmail.com> wrote: >> >> CL-USER> (cffi::list-foreign-libraries) >> >> (... >> >> #<CFFI:FOREIGN-LIBRARY >> >> :LIBCAIRO #P"/usr/local/Cellar/cairo/1.12.16_1/lib/libcairo.dylib" >> >> (truename=#P"/usr/local/Cellar/cairo/1.12.16_1/lib/libcairo.2.dylib")>) >> >> CL-USER> >> >> >> >> However, when I attempt to load libgdk-x11-2.0.0.dylib it complains that >> >> it cannot find a particular symbol in /usr/local/lib/libcairo.dylib. Why >> >> is it complaining about /usr/local/lib/libcairo.dylib? >> > >> > Most of those dylibs are symlinks and libgdk may depend on a name >> > which exists in /usr/local/lib but not /usr/local/Cellar, maybe? ldd >> > can tell you what a given dylib depends on. >> >> As Jim is on macOS there is no ldd. The command to use is >> >> otool -L /usr/local/lib//libcairo.dylib >> >> Seeing that Jim uses homebrew to install Cairo it is worth mentioning that >> brew install … also generates (normally) an entry in /usr/local/lib . That >> is why I always stick to using /usr/local/lib/libxyz.dylib paths when I want >> to ensure a particular library to be loaded. >> >> Best, >> Frank >> >> >> >