PHP Manual: Checks if the class has been defined

Description

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

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.

Changelog

Version	Description
5.0.2	No longer returns `TRUE` for defined interfaces. Use interface_exists.

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();
}

?>

class_exists

Description

Parameters

Return Values

Changelog

Examples

See Also