Re: Public header files

[Jef Driesen]

On 01/03/10 19:35, Ralf Wildenhues wrote:
> Hello Jef,
>
> * Jef Driesen wrote on Mon, Mar 01, 2010 at 01:33:46PM CET:
> > How do I get information generated by autotools into my public
> > header files? For instance I want to define version numbers
> > somewhere in my configure.ac file, and have the same numbers appear
> > in a public header file without having to modify both files
> > manually? Another example is that my library needs a 64bit integer
> > type for its public api.
> >
> > Since a config.h header files is not supposed to be public, that's
> > not an option. But how can I do this correctly?
>
> Use a second config header.  Its input template will not be generated by
> autoheader; you write it yourself.  That way you can be sure to only put
> safe stuff in there.

Can you give me some info to guide me into the right direction. I don't 
know where or what I should be looking for.

> As much as possible, try to think of the possibility that your users may
> enable or disable presence of a 64bit integer with compiler command line
> options they pass to their package's configure script, or want a
> multilib-like installation, where they adjust --libdir for different
> ABI versions of your package; you should strive to have as few variation
> in public headers as possible, ideally both versions install the same
> header files (and only differ in semantics through preprocessor means).

For the 64bit integer, I am using the preprocessor right now:

#ifdef _WIN32
typedef __int64 ticks_t;
#else
typedef long long int ticks_t;
#endif

It works fine for every system I have access too, but long long is not 
standard and thus not guaranteed to be present. So I just want to make 
sure it will work on other systems too.

> An alternative of the above approach is the AX_PREFIX_CONFIG_H macro
> from the Autoconf Macro Archive.

I'll have a look at that too.