(PHP 4, PHP 5, PHP 7)
class_exists — ������Ƿ��Ѷ���
$class_name
[, bool $autoload = true
] ) : bool���ָ�������Ƿ��Ѷ��塣
����� class_name
��ָ�����Ѿ����壬�˺�������
TRUE������ FALSE��
Example #1 class_exists() ����
<?php
// ʹ��ǰ������Ƿ����
if (class_exists('MyClass')) {
$myclass = new MyClass();
}
?>
Example #2 autoload parameter ����
<?php
function __autoload($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();
}
?>