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class_exists

Checks if the class has been defined (PHP 4, PHP 5)
bool class_exists ( string class_name [, bool autoload] )

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. Defaults to TRUE.

Return Values

Returns TRUE if class_name is a defined class, FALSE otherwise.

ChangeLog

VersionDescription
5.0.2 No longer returns TRUE for defined interfaces. Use interface_exists().
5.0.0 The autoload parameter was added.

Examples

Example 373. class_exists() example

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

?>


Example 374. 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();
}

?>