constant

(PHP 4 >= 4.0.4, PHP 5, PHP 7)

Returns the value of a constant

mixed constant ( string $name )

Return the value of the constant indicated by name.

constant() is useful if you need to retrieve the value of a constant, but do not know its name. I.e. it is stored in a variable or returned by a function.

This function works also with class constants.

Parameters:

name

The constant name.

Returns:

Returns the value of the constant, or NULL if the constant is not defined.

Exception:

An E_WARNING level error is generated if the constant is not defined.

Examples:

constant() example

<?php

define("MAXSIZE", 100);

echo MAXSIZE;
echo constant("MAXSIZE"); // same thing as the previous line


interface bar {
    const test = 'foobar!';
}

class foo {
    const test = 'foobar!';
}

$const = 'test';

var_dump(constant('bar::'. $const)); // string(7) "foobar!"
var_dump(constant('foo::'. $const)); // string(7) "foobar!"

?>