Re: Retrieving the "include" directory for Emacs Modules

[Eli Zaretskii]

> Date: Sun, 08 Dec 2024 11:48:24 -0500
> From:  Stefan Monnier via Users list for the GNU Emacs text editor 
> <help-gnu-emacs@gnu.org>
> 
> >> >   #include <emacs-module.h>
> >> >
> >> > and that's it.  Or what am I missing?
> >> 
> >> That presumes that Emacs is installed system-wide (and "properly").
> >
> > What other way is there to install Emacs?
> 
> Compile manually and run from the build tree?

That's called "run uninstalled".  And in that case, the user who does
that knows very well where the header lives: in the same directory
from which he/she runs Emacs.

> Uncompress a downloaded pre-compiled archive into a directory and just
> use it from there (AFAIK, very common under macOS and Windows)?

If that doesn't place emacs-module.h in the system-wide include
directory, it is a broken installation.

> With luck on some systems the C (or other) compiler is installed in
> a similar way (i.e. in its own subdirectory, siloed from Emacs).

That's not how multi-package installation should be organized if the
user wants the packages to cooperate.

> >> When the compilation of the module is initiated from within Emacs, it
> >> would make a lot of sense for this "ambient" Emacs to be able to tell
> >> `make/gcc/younameit` explicitly and reliably where its own
> >> `emacs-module.h` can be found.
> > But if Emacs is "not installed properly", we don't know that.
> 
> Emacs *should* know that, just like it knows where is its
> `lisp-directory`.

That's impractical expectation.  Recall how hard we worked to find the
pdumper file and the preloaded *.eln files, what with all the tricks
people use when installing Emacs.  I'm not interested in adding
another burden to our maintenance so that Emacs will paper over broken
installations.  Sorry.