(PHP 4, PHP 5, PHP 7, PHP 8)
class_exists — Checks if the class has been defined
$class
, bool $autoload
= true
): boolThis function checks whether or not the given class has been defined.
class
The class name. The name is matched in a case-insensitive manner.
autoload
Whether to autoload if not already loaded.
Returns true
if class
is a defined class,
false
otherwise.
Example #1 class_exists() example
<?php// Check that the class exists before trying to use itif (class_exists('MyClass')) { $myclass = new MyClass();}?>
Example #2 autoload
parameter example
<?phpspl_autoload_register(function ($class_name) { include $class_name . '.php'; // Check to see whether the include declared the class if (!class_exists($class_name, false)) { throw new LogicException("Unable to load class: $class_name"); }});if (class_exists(MyClass::class)) { $myclass = new MyClass();}?>