(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
is_a — Checks whether the object is of a given type or subtype
Determines if the given object_or_class is the
class object type,
or has class as one of its supertypes.
object_or_classA class name or an object instance.
classThe class or interface name
allow_string
If this parameter set to false, string class name as object_or_class
is not allowed. This also prevents from calling autoloader if the class doesn't exist.
Returns true if object_or_class is the
class object type,
or has class as one of its supertypes, false otherwise.
Example #1 is_a() example
<?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 Using the instanceof operator
<?php
if ($WF instanceof WidgetFactory) {
echo 'Yes, $WF is a WidgetFactory';
}
?>