Find a library in /usr/local/lib?

[rjzak]

I've got a project looking for zlib-ng, which is installed as:

❯ ls -la /usr/local/lib/libz-ng* 
-rw-r--r-- 1 root root 249590 Feb 12 10:11 /usr/local/lib/libz-ng.a
lrwxrwxrwx 1 root root     16 Feb 12 10:11 /usr/local/lib/libz-ng.so -> libz-ng.so.2.1.6
lrwxrwxrwx 1 root root     16 Feb 12 10:11 /usr/local/lib/libz-ng.so.2 -> libz-ng.so.2.1.6
-rwxr-xr-x 1 root root 214904 Feb 12 10:11 /usr/local/lib/libz-ng.so.2.1.6

Without Mold, the gcc linker finds it, but Mold does not. Does mold use the paths in /etc/ld.so.conf? This project also uses CMake, for which I could have probably done a better job with the CMakeLists.txt file :)

[rui314]

Maybe your CMakeLists.txt does not use find_library to find libz-ng? I believe the macro automatically adds -L/usr/local/lib if it found the specified library in /usr/local/lib.

[rjzak]

Seems not to, at least for me. I suppose I don't know why gcc/ld finds it and mold didn't, but it seems my CMake file wasn't being explicit with the library path.

[rui314]

GNU ld hardcodes some library paths, while mold and lld do not, facilitating cross-compilation. In general, it is not a good idea to rely on implicit library paths. You may want to fix your CMake file.