Re: Use of config.h: summary of responses.

[Andre Caldas]

Hi,

> If example-util's build system does not check for the availability of const,
> and example-util uses libexample's header files which do use const, the
> build will fail.
>
> On the other hand, if libexample's build system detected a lack of const and
> includes a workaround (for example, defining "const" away with a
> preprocessor macro), then later example-util is compiled in an environment
> that *does* have const, building example-util with libexample's header files
> will change the behavior of example-util in unexpected and unnecessary ways.
>
>
> The former can be mitigated by having libexample's developers distribute a
> libexample.m4 file which can be referenced during example-util's build
> environment setup, to avoid requiring that example-util's developers track
> libexample's individual requirements.

I had heard about prefixed config.h files, and I thought they were the 
solution to my problem. But I think yours is a much better solution. I 
will try to change my projects to follow this approach.

But this also means that I have to learn how to write *.m4 files :-(
Can you give me some hints on:
        * How to write this libexample.m4 ( a kind of sketch )
        * How to install libexample.m4
                (something like this in a Makefile.am:
                        libexample_so_M4MACROS = libexample.m4
                        libexample_m4dir = $(m4dir)
                )
        * Where to install the *.m4 file

	* Whether I should or not include a #ifdef HAVECONFIG_H in my installed 
headers

Writing this e-mail I just realized that if there is a standard way to 
create and install libexample.m4 then most of the problems can be 
solved. Does this standard way exists?

Thank you,
Andre Caldas.