How can constants be defined once and reused through all files?

Question

I\'m trying to set up a site that has many reusable headers/footers, style information, etc. Is there anyway to define a global constant/function that can be reused from any

Answer 1

I have been using:

set_include_path( get_include_path() . PATH_SEPARATOR . $_SERVER['DOCUMENT_ROOT'] );
include_once('glob.php');

Which sets my include path right at the root of my site. Not sure if it will work for you though, or if there is a better way?