Undefined constant “%s¶
Description¶
The requested constant doesn’t exist.
The constant may be defined at different places in the code :
In the running code: it could be in a different file, which was not included yet, or later in the code.
In a dependency: use the name of the constant to find which dependency defines this constant. Then, make sure the dependency is satisfied.
In an extension: use the name of the constant to find which PHP extension defines this constant. For example,
XML_PI_NODE
is from the ext/xml extension, which may not be in the current PHP engine.
There is a distinct message for class constants.
Example¶
<?php
// early usage of the constant
echo A;
const A = 2;
?>
Literal Examples¶
Undefined constant “A”
Undefined constant “XML_PI_NODE”
Solutions¶
Find the actual name of the requested constant.
Check the namespace, or its import:
use const
.Check if the constant is used after its definition.
Check if the constant is defined in a PHP extension, and the extension was forgotten.
Check if the constant is defined in a dependency, and the dependency was forgotten.