Question

I’m using constants to set various configuration variables within a script.

The INC_PATH constant is defined within the script that includes the class library.

define('INC_PATH',$_SERVER['DOCUMENT_ROOT'].'includes/');
include('class.lib.php');

The class library contains various include(‘someClass.php’) lines. It also contains:

require(INC_PATH.'DB.class.php');

The class library throws a notice:

Use of undefined constant INC_PATH - assumed 'INC_PATH'

How is the class library not able to see that the INC_PATH constant has been defined? I thought constants were global?

Answer 1

Yes, but they must be defined before:

<?php
echo INC_PATH; //undefined
define('INC_PATH', "foo");
echo INC_PATH; //defined

In response to your comment

I can’t reproduce that:

a.php

<?php
define('INC_PATH',$_SERVER['DOCUMENT_ROOT']."/");
include('b.php.inc');

b.php.inc

<h1><?php require(INC_PATH . "c.php.inc"); ?></h1>

c.php.inc

<?php echo INC_PATH; ?>

Asking for a.php gives:

<h1>U:/htdocs/</h1>