setting getting variable to be changed in production and read in my C module

[eeadev dev <eeadev@xxxxxxxxx>]

I have to write a set of variable to be read from my C module. Those variable could be change when the code is in production, similar to what u would write in a java properties file.

What is the proper way to do it and which functions to use?

1. write the in the httpd.conf (what is the API for getting/setting a var visible in all the apache web server)
2. write them in the [module].conf (what is the API for getting/setting a var visible in all my module)
   
3. write them in another file, opening it with c open and parse it in the C way
   

I saw there is this API apr_env_* where are those variable meant to be?

thanks