Check if a class constant exists

Question

How can I check if a constant is defined in a PHP class?

class Foo {
    const BAR = 1;
}

Is there something like property_exists()

Answer 1

Yes, just use the class name in front of the constant name:

defined('SomeNamespace\SomeClass::CHECKED_CONSTANT');

http://www.php.net/manual/en/function.defined.php#106287