class_exists
(PHP 4, PHP 5)
class_exists -- Checks if the class has been defined
Description
bool
class_exists ( string class_name [, bool autoload] )
This function checks if the given class have been defined.
Parameters
class_name
The class name
autoload
Whether to call __autoload or not by default
Return Values
Returns TRUE if class_name is a defined class,
FALSE otherwise.
Examples
Example 1. class_exists() example
<?php
// Check the class exists before trying to use it
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
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Example 2. autoload parameter example
<?php
function __autoload($class)
{
include($class . '.php');
// Check to see if the include declared the class
if (!class_exists($class, false)) {
trigger_error("Unable to load class: $class", E_USER_WARNING);
}
}
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
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