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Undefined constant %s::%s

Description

The requested class constant could not be found.

The error message is distinct for the global constants, although there is no mention of class in this one.

Example

<?php

class X {
	const Z = 1;
	private A = 2;
}

echo X::Y; 

?>

Literal Examples

  • Undefined constant X::CONSTANT

Alternatives

  • Find the actual name of the requested class constant.
  • Find the actual class of the requested class constant.
  • Check the namespace, or its import.
  • Check the visibility of the class constant: it may be private, or protected.
  • Check the autoload system, to make sure the definition could be found.
  • Define the class constant in the class, or its traits, interfaces or parents.

In previous PHP versions, this error message used to be :ref:undefined-class-constant-'%s::%s'.