class_exists

(PHP 4, PHP 5, PHP 7, PHP 8)

class_existsChecks if the class has been defined

Description

class_exists(string $class, bool $autoload = true): bool

This function checks whether or not the given class has been defined.

Parameters

class

The class name. The name is matched in a case-insensitive manner.

autoload

Whether to autoload if not already loaded.

Return Values

Returns true if class is a defined class, false otherwise.

Examples

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();}?>

See Also