(PHP 4 >= 4.2.0, PHP 5, PHP 7)
is_a — ����������ڸ��������Ǵ˶���ĸ����� TRUE
$object
, string $class_name
[, bool $allow_string = FALSE
] ) : bool
��� object �Ǹ��������Ǵ˶���ĸ��ࡣ
objectThe tested object
class_nameThe class name
allow_string
If this parameter set to FALSE, string class name as object
is not allowed. This also prevents from calling autoloader if the class doesn't exist.
Returns TRUE if the object is of this class or has this class as one of
its parents, FALSE otherwise.
| �汾 | ˵�� |
|---|---|
| 5.3.9 |
Added allow_string parameter
|
| 5.3.0 |
This function is no longer deprecated, and will therefore
no longer throw E_STRICT warnings.
|
| 5.0.0 |
This function became deprecated in favour of the
instanceof
operator. Calling this function will result in an
E_STRICT warning.
|
Example #1 is_a() ����
<?php
// define a class
class WidgetFactory
{
var $oink = 'moo';
}
// create a new object
$WF = new WidgetFactory();
if (is_a($WF, 'WidgetFactory')) {
echo "yes, \$WF is still a WidgetFactory\n";
}
?>
Example #2 �� PHP 5 ��ʹ�� instanceof �����
<?php
if ($WF instanceof WidgetFactory) {
echo 'Yes, $WF is a WidgetFactory';
}
?>