Change search path for dependency()?

[DidierMalenfant]

I'm trying to build glib, which uses mason as its build system, as a universal binary on macOS.

When linking it resolves libpcre to my system one (which is not a universal binary) instead of the one I've built myself (which is). The linker command line contains:

-Wl,-rpath,/opt/homebrew/Cellar/pcre2/10.42/lib /opt/homebrew/Cellar/pcre2/10.42/lib/libpcre2-8.dylib

Now this seems to be the result of:

      pcre2 = cc.find_library('pcre2-8', required : false)

in the mason.build file but I can't find a way to affect where this find_library is looking for its target.

I've tried setting LIBRARY_PATH in my env, tried passing -L options to the linker via c_link_args to no avail.

Ideally I'm looking for an environment or command line solution as I'm trying not to modify the library's files if possible.

[eli-schwartz]

Now this seems to be the result of:

      pcre2 = cc.find_library('pcre2-8', required : false)

in the mason.build file but I can't find a way to affect where this find_library is looking for its target.

That's only used on Windows. The full check is:

pcre2 = dependency('libpcre2-8', version: pcre2_req, required: false, default_options: ['default_library=static'])
if not pcre2.found()
  if cc.get_id() == 'msvc' or cc.get_id() == 'clang-cl'
  # MSVC: Search for the PCRE2 library by the configuration, which corresponds
  # to the output of CMake builds of PCRE2.  Note that debugoptimized
  # is really a Release build with .PDB files.
    if vs_crt == 'debug'
      pcre2 = cc.find_library('pcre2d-8', required : false)
    else
      pcre2 = cc.find_library('pcre2-8', required : false)
    endif
  endif
endif

# Try again with the fallback
if not pcre2.found()
  pcre2 = dependency('libpcre2-8', version: pcre2_req, allow_fallback: true, default_options: ['default_library=static'])
  assert(pcre2.type_name() == 'internal')

...

Notice:

• dependency() is always used first, and checks with pkg-config, so you can override this by setting $PKG_CONFIG_PATH
• when using msvc cl.exe or clang-cl.exe, and pkg-config failed, try searching the cc.find_library() search path
• final fallback is to retry dependency() knowing it will fail, in order to use the wrap dependency fallback mechanism

[DidierMalenfant]

Yep, I stand corrected, the dependency call is indeed where the magic takes place. Thanks!

So I'm assuming just setting PKG_CONFIG_PATH before calling meson setup will do the right thing?

Is there a way to list all the dependency paths found after a setup command kinda like cmake does?

[DidierMalenfant]

Ok so it looks like PKG_CONFIG_PATH is not a path for libraries but a path for pkg-config config files. Since my build of pcre2 doesn't seem to generate those, I manually created one as a test. This now works as expected:

PKG_CONFIG_PATH=/Users/didier/Desktop/FSUAE-Build/deps/lib/pkgconfig pkg-config --libs pcre2-8
-L/Users/didier/Desktop/FSUAE-Build/deps/lib -lpcre2-8

same path can then be passed to configure the mason build:

PKG_CONFIG_PATH=/Users/didier/Desktop/FSUAE-Build/deps/lib/pkgconfig meson setup build ...

[eli-schwartz]

If you look at the log file in builddir/meson-logs/meson-log.txt it will produce a debug report of the exact pkg-config command line run, with the environment variables it uses, and the stdout/stderr that the subprocess produced.

[DidierMalenfant]

Thank you for your help!