Header files in PHP

Folks: Over the years, I've heard a lot of back and forth about require_once, require, include, include_once and he like. Most of it centers around the CPU time taken to execute these calls. The "C" way to do something similar is to define a constant in a header file and then check for its existence in the C code file. In PHP, this would be roughly like this: LIBRARY FILE: define('CONST_DATE', TRUE); CODE FILE: if (!defined('CONST_DATE')) include('date.lib.php'); Has anyone ever compared execute times to see if something like this would be "cheaper" than include/require[_once]? Any thoughts on it? Paul -- Paul M. Foster http://noferblatz.com http://quillandmouse.com