[php] re-declare function error

This is how my site works: Index.php is the shell of the site. It has all the graphics and layout tables. Each link is structured like index.php?sec=contact. I use $_GET to find which section the user wants to go to. And then I load the page content by running secCode(). secCode() is the function in contact.php, for example, that contains all the contact content.


$section = $_GET['sec'];
$section .= ".php";
include("$section");
secCode();

I’ve done include(“constants.php”) in index.php, but whenever I load a whateverSection.php, the constants are no longer in scope. So I re-include constants.php within the section code. This is where the re-declare error lies. How do I fix it?