Re: how to let configure know include and library path for library foo?

[Peter Johansson]

Hi Sebastien,

On 1/24/2019 8:16 PM, Sébastien Hinderer wrote:
> Dear all,
>
> When an autoconf-driven project has a dependency on library foo, what's the
> best / recommended way to let users specify the directories for header
> files and library files when configuring the project?

I would expect there are different opinions on this. As a user I think 
the best way is to rely on variables CPPFLAGS, CFLAGS (or CXXFLAGS for 
C++) and LDFLAGS. If explained in the README it is pretty 
straightforward for users to e.g. call

./configure CPPFLAGS=-I/path/to/includedir

or similarly

./configure LDFLAGS=-L/path/to/libdir



> For the XWindow system, for instance, there are the --x-includes=DIR
> and --x-libraries=DIR options, and also --with-x to enable / disable X.
>
> I assume it's good to also provide three options for each library: one
> to let configure know whether it should be enabled or not, i.e. an
> equivalent of --with-x,

An option --without-foo is useful if the foo is optional, i.e., it's 
possible to build and use your package without foo. If foo is required 
an option --without-foo does not make much sense. I had a use case when 
a co-maintainer wanted to be able 'make dist' without required 
dependencies. Not really recommended as I would recommend using 'make 
distcheck' rather than 'make dist' for that.

Whether you want the default

./configure

behave as

./configure --with-foo

or as

./configure --without-foo

depends very much on the situation and the different cases how to 
accomplish that is well described in the manual.

Hope that helps,

Peter

>   and two options to specify the header and
> library directories. But, of course, it is not possible to define
> --foo-includes=DIR and --foo-libraries=DIR as is done for X, so is one
> supposed to use AC_ARG_VAR to achieve this?
>
> Many thanks in advance for your recommendations,
>
> Sébastien.
>
> _______________________________________________
> Autoconf mailing list
> address@hidden
> https://lists.gnu.org/mailman/listinfo/autoconf