Re: Retrieving the "include" directory for Emacs Modules

[Eli Zaretskii <eliz@gnu.org>]

> Date: Tue, 24 Dec 2024 10:30:41 -0500
> From:  Stefan Monnier via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>
> 
> > Careful: the above might pick up header files private to source
> > distributions if you have them on your system (i.e., if you build
> > packages locally from sources).  By contrast, this discussion is about
> > _public_ header files, ones installed with the purpose of letting
> > other packages interface with the package whose header file is
> > installed.
> 
> I'll let you judge.
> 
> 
>         Stefan
> 
> 
> % locate '*.h' | sed 's|[^/]*$||' | sort -u | grep -v 'monnier\|/usr/include'
> /usr/lib/clisp-2.49.93+/base/
> /usr/lib/clisp-2.49.93+/linkkit/
> /usr/lib/gcc/x86_64-linux-gnu/10/include/
> /usr/lib/gcc/x86_64-linux-gnu/10/include/sanitizer/
> /usr/lib/gcc/x86_64-linux-gnu/12/include/
> /usr/lib/gcc/x86_64-linux-gnu/12/include/sanitizer/
> /usr/lib/ghc/
> /usr/lib/ghc/base-4.15.1.0/include/
> /usr/lib/ghc/bytestring-0.10.12.1/include/
> /usr/lib/ghc/ghc-9.0.2/include/
> /usr/lib/ghc/ghc-bignum-1.1/include/
> /usr/lib/ghc/include/
> /usr/lib/ghc/include/rts/
> /usr/lib/ghc/include/rts/prof/
> /usr/lib/ghc/include/rts/storage/
> /usr/lib/ghc/include/stg/
> /usr/lib/ghc/process-1.6.13.2/include/
> /usr/lib/ghc/time-1.9.3/include/
> /usr/lib/ghc/unix-2.7.2.2/include/
> /usr/lib/gprolog/include/
> /usr/lib/grub/i386-pc/
> /usr/lib/grub/x86_64-efi/
> /usr/lib/haskell-packages/ghc/lib/x86_64-linux-ghc-9.0.2/primitive-0.7.3.0-EikPDi9CXNiB9f5MDJybeY/include/
> /usr/lib/haskell-packages/ghc/lib/x86_64-linux-ghc-9.0.2/vector-0.12.3.1-TXkE6leK98EdYcmdk29JF/include/
> /usr/lib/jvm/java-17-openjdk-amd64/include/
> /usr/lib/jvm/java-17-openjdk-amd64/include/linux/
> /usr/lib/llvm-14/lib/clang/14.0.6/include/
> /usr/lib/llvm-14/lib/clang/14.0.6/include/openmp_wrappers/
> /usr/lib/llvm-14/lib/clang/14.0.6/include/ppc_wrappers/
> /usr/lib/llvm-14/lib/clang/14.0.6/include/xray/
> /usr/lib/ocaml/caml/
> /usr/lib/ocaml/zarith/
> /usr/lib/python3/dist-packages/dulwich/
> /usr/lib/python3/dist-packages/greenlet/
> /usr/lib/python3/dist-packages/greenlet/platform/
> /usr/lib/python3/dist-packages/lxml/
> /usr/lib/python3/dist-packages/lxml/includes/
> /usr/lib/swi-prolog/include/
> /usr/lib/swi-prolog/include/sicstus/
> /usr/lib/swi-prolog/include/Yap/
> /usr/lib/x86_64-linux-gnu/dbus-1.0/include/dbus/
> /usr/lib/x86_64-linux-gnu/glib-2.0/include/
> /usr/lib/x86_64-linux-gnu/perl/5.36.0/CORE/
> /usr/lib/x86_64-linux-gnu/perl5/5.36/B/Hooks/OP/Check/Install/
> /usr/lib/x86_64-linux-gnu/perl5/5.36/Cairo/Install/
> /usr/lib/x86_64-linux-gnu/perl5/5.36/Encode/
> /usr/lib/x86_64-linux-gnu/perl5/5.36/Glib/Install/
> /usr/lib/xemacs-21.4.24/x86_64-linux-gnu/include/
> /usr/lib/xemacs-21.4.24/x86_64-linux-gnu/include/m/
> /usr/lib/xemacs-21.4.24/x86_64-linux-gnu/include/s/
> /usr/share/cmake-3.25/include/
> /usr/share/cmake-3.25/Modules/
> /usr/share/cups/ppdc/
> /usr/share/doc/bison/examples/c/mfcalc/
> /usr/share/doc/guile-3.0-dev/examples/compat/
> /usr/share/doc/libzstd-dev/examples/
> /usr/share/doc/nettle-dev/examples/
> /usr/share/doc/printer-driver-pnm2ppa/pl/
> /usr/share/doc/zlib1g-dev/examples/
> /usr/share/gettext/
> /usr/share/go-1.19/misc/cgo/life/testdata/
> /usr/share/go-1.19/misc/cgo/test/
> /usr/share/go-1.19/misc/cgo/testplugin/testdata/issue25756/plugin/
> /usr/share/go-1.19/misc/cgo/testsovar/testdata/
> /usr/share/go-1.19/misc/cgo/test/testdata/gcc68255/
> /usr/share/go-1.19/misc/cgo/test/testdata/issue20266/
> /usr/share/go-1.19/misc/cgo/test/testdata/issue26213/
> /usr/share/go-1.19/misc/cgo/test/testdata/issue27054/
> /usr/share/go-1.19/misc/swig/callback/
> /usr/share/go-1.19/pkg/include/
> /usr/share/go-1.19/src/crypto/internal/boring/
> /usr/share/go-1.19/src/debug/dwarf/testdata/
> /usr/share/go-1.19/src/debug/gosym/testdata/
> /usr/share/go-1.19/src/runtime/
> /usr/share/go-1.19/src/runtime/cgo/
> /usr/share/grub/
> /usr/share/libtool/
> /usr/share/libtool/libltdl/
> /usr/share/perl/5.36.0/Encode/
> /usr/share/smartmontools/
> /usr/src/libdvd-pkg/build/
> /usr/src/libdvd-pkg/build/msvc/
> /usr/src/libdvd-pkg/build/src/
> /usr/src/libdvd-pkg/build/src/dvdcss/
> /usr/src/linux-apfs-rw-0.3.0-1/
> /usr/src/linux-apfs-rw-0.3.0-1/lzfse/
> /var/lib/smartmontools/drivedb/
> % 

Those under /usr/lib are looked in by the relevant compilers (they are
include directories private to those compilers, hard-coded into them
when they are built).  Those under /usr/share are private to the
relevant packages, and are either examples or test suites (thus AFAIU
unrelated to the issue at hand here).  Those under /usr/src are what I
mentioned: private headers needed to build a package.