(PHP 4, PHP 5)
class_exists — Checks if the class has been defined
$class_name
[, bool $autoload = true
] )This function checks whether or not the given class has been defined.
class_nameThe class name. The name is matched in a case-insensitive manner.
autoloadWhether or not to call __autoload by default.
Returns TRUE if class_name is a defined class,
FALSE otherwise.
| Version | Description |
|---|---|
| 5.0.2 |
No longer returns TRUE for defined interfaces. Use
interface_exists().
|
| 5.0.0 |
The autoload parameter was added.
|
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();
}
?>