PHP

wordpress how to string multple function.php files together

<?php 
/*
 * functions.php
 * 
 */
require_once( __DIR__ . '/includes/null-meta-compare.php');
require_once( __DIR__ . '/includes/older-examples.php');
require_once( __DIR__ . '/includes/wp-admin-menu-classes.php');
require_once( __DIR__ . '/includes/admin-menu-function-examples.php');

// WA: Adding a Taxonomy Filter to Admin List for a Custom Post Type?
// http://wordpress.stackexchange.com/questions/578/
require_once( __DIR__ . '/includes/cpt-filtering-in-admin.php'); 
require_once( __DIR__ . '/includes/category-fields.php');
require_once( __DIR__ . '/includes/post-list-shortcode.php');
require_once( __DIR__ . '/includes/car-type-urls.php');
require_once( __DIR__ . '/includes/buffer-all.php');
require_once( __DIR__ . '/includes/get-page-selector.php');

// http://wordpress.stackexchange.com/questions/907/
require_once( __DIR__ . '/includes/top-5-posts-per-category.php'); 

// http://wordpress.stackexchange.com/questions/951/
require_once( __DIR__ . '/includes/alternate-category-metabox.php');  

// http://lists.automattic.com/pipermail/wp-hackers/2010-August/034384.html
require_once( __DIR__ . '/includes/remove-status.php');  

// http://wordpress.stackexchange.com/questions/1027/removing-the-your-backup-folder-might-be-visible-to-the-public-message-generate
require_once( __DIR__ . '/includes/301-redirects.php');