Re: Including sysconfdir in CPPFLAGS

[Guido Draheim]

Peter Eisentraut wrote:
> Fredrik Tolf writes:
>
>
> > How do I get the sysconfdir into a cpp macro if I use automake as
> > well? Should I do it through a config header, or should I do it via
> > some automake contraption? Should I just add it to CPPFLAGS? Please
> > tell me.
>
>
> The Autoconf manual tells the tale:
>
>    A corollary is that you should not use these variables except in
> Makefiles.  For instance, instead of trying to evaluate `datadir' in
> `configure' and hardcoding it in Makefiles using e.g.
> `AC_DEFINE_UNQUOTED(DATADIR, "$datadir")', you should add
> `-DDATADIR="$(datadir)"' to your `CPPFLAGS'.

A corollary to gnu coding standards, and a corollary with little
impact as `make` and `make install` are still two stages. In the
bottom line, it does not matter. - The reality however is even
different: do not use sysconfdir in your program sources! people
are still thinking to put config files in there but that's
inherently wrong. If you want runtime configs, you need to do a
lot of runtime checks and go for ${HOME} first, and some package
specific ${MYPKGCONFIG} second, and only as a fallback go for
a system directory. In that case, do not call it $sysconfdir but
a make/subst MYPCKCONFIG that has a configure.ac fallback to
${sysconfdir}, with the effect that in all build stages the
_specific_ path can be overridden. And that makes for the thing
said above: do not use sysconfdir in your program sources!

cheers,
-- guido                               http://AC-Archive.sf.net
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