Question

I would like to display the explicit path to a library which will be used in the linking stage of compilation. I want to do this so that I can add the library as a dependency to a separate object file.

In other words, I often link using:

g++ myFile.cpp -Lsomewhere -Lelse -Lhere -Lthere -lfoo

Is there a way to coerce g++, ld, ldd, or something else to resolve ‘-lfoo’ using the -L’s without actually linking anything so that I can use the explicit path as a dependency? For more explicit info, see Makefile Updated Library Dependency.

Answer 1

This isn’t ideal, and I hope there is a cleaner answer, but you can get the default search paths from gcc, then search each one for the files. Here it is in GNU make:

libnams = foo bar
dirs = somewhere else here there
dirs += $(subst :, ,$(subst =,,$(word 2,$(shell gcc -print-search-dirs | grep libraries))))
exts = a so
paths = $(foreach L, $(libnams), \
           $(firstword $(foreach D, $(dirs), \
              $(foreach E, $(exts), \
                 $(wildcard $(D)/lib$(L).$(E))))))