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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?
682
A constant is an identifier (name) for a simple value. The value cannot be changed during the script. A valid constant name starts with a letter or underscore (no $ sign before the constant name).
Code Inspection: Undefined constantReports the references to constants that are not found in the project files, configured include paths, or among the PHP predefined constants.
Q 3 - Which of the following is correct about constants vs variables in PHP? A - Constants may be defined and accessed anywhere without regard to variable scoping rules.
Constants can be defined using the const keyword, or by using the define()-function. While define() allows a constant to be defined to an arbitrary expression, the const keyword has restrictions as outlined in the next paragraph. Once a constant is defined, it can never be changed or undefined.
Yes, but they must be defined before:
<?php
echo INC_PATH; //undefined
define('INC_PATH', "foo");
echo INC_PATH; //defined
I can't reproduce that:
<?php
define('INC_PATH',$_SERVER['DOCUMENT_ROOT']."/");
include('b.php.inc');
<h1><?php require(INC_PATH . "c.php.inc"); ?></h1>
<?php echo INC_PATH; ?>
Asking for a.php gives:
<h1>U:/htdocs/</h1>
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