define(): Argument #3 ($case_insensitive) is ignored since declaration of case-insensitive constants is no longer supported

Description

The third argument of define() used to allow the creation of a case-insensitive global constant. The constant in the code would have been accessible with A or a, without distinction. This feature has been deprecated in PHP 7.3 and abandonned in PHP 8.0. For backward compatibility, the third argument is not reported as an error, but a warning. The constant is not case insensitive any way. Adding a fourth argument is a fatal error, and has no meaning.

Example

<?php

define('A', 'b', true);

?>

Solutions

• Remove the third argument in the define() call.

In more recent PHP versions, this error message is now define(): Declaration of case-insensitive constants is deprecated.