gistfile1.php

// ----------------------- Set the number of a custom post type posts per page
add_filter( 'pre_get_posts', 'be_archive_query' );
// @link http://www.billerickson.net/customize-the-wordpress-query/
function be_archive_query( $query ) {
	if( $query->is_main_query() && $query->is_post_type_archive('code') ) {
		$query->set( 'posts_per_page', 24 );
	}
}