class_exists

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

class_existsChecks if the class has been defined

Опис

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

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

Параметри

class

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

autoload

Whether to autoload if not already loaded.

Значення, що повертаються

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

Приклади

Приклад #1 class_exists() example

<?php
// Check that the class exists before trying to use it
if (class_exists('MyClass')) {
$myclass = new MyClass();
}

?>

Приклад #2 autoload parameter example

<?php
spl_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();
}

?>

Прогляньте також