constant()

The constant() function is a PHP native function, which provide the value of a declared global constant, a class constant or an enumeration case.

For class constant and enumeration cases, it may be replaced with the dynamic class constant syntax, introduced in PHP 8.3.

<?php

const A = 1;

echo constant('A');

enum E: string {
    case B = 'abc';
    const C = 'def';
}

echo constant('E::B')->value; // abc
echo constant('E::C');        // def

?>

Documentation

Related : Dynamic Class Constant, Class Constant Syntax, Dynamic Constant