W3cubDocs

/PHP

class_exists

(PHP 4, PHP 5, PHP 7)

class_exists — Checks if the class has been defined

Description

class_exists ( string $class_name [, bool $autoload = true ] ) : bool

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

Parameters

class_name

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

autoload

Whether or not to call __autoload by default.

Return Values

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

Examples

Example #1 class_exists() example

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

?>

Example #2 autoload parameter example

<?php
function __autoload($class)
{
    include($class . '.php');

    // Check to see whether the include declared the class
    if (!class_exists($class, false)) {
        trigger_error("Unable to load class: $class", E_USER_WARNING);
    }
}

if (class_exists('MyClass')) {
    $myclass = new MyClass();
}

?>

See Also

© 1997–2020 The PHP Documentation Group
Licensed under the Creative Commons Attribution License v3.0 or later.
https://www.php.net/manual/en/function.class-exists.php