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() or method_exists() for class constants? Or can I just use defined("Foo::BAR")?

Answer 1

You can check if a constant is defined with the code below:

<?php if(defined('className::CONSTANT_NAME')){   //defined }else{   //not defined } 

Answer 2

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