is_subclass_of

is_subclass_of

(PHP 4, PHP 5)

is_subclass_of --  Returns TRUE if the object has this class as one of its parents

Description

bool is_subclass_of ( mixed object, string class_name )

This function returns TRUE if the object object, belongs to a class which is a subclass of class_name, FALSE otherwise.

Note: Since PHP 5.0.3 you may also specify the object parameter as a string (the name of the class).

Example 1. is_subclass_of() example

<?php
// define a class
class WidgetFactory
{
  var
$oink = 'moo';
}

// define a child class
class WidgetFactory_Child extends WidgetFactory
{
  var
$oink = 'oink';
}

// create a new object
$WF = new WidgetFactory();
$WFC = new WidgetFactory_Child();

if (
is_subclass_of($WFC, 'WidgetFactory')) {
  echo
"yes, \$WFC is a subclass of WidgetFactory\n";
} else {
  echo
"no, \$WFC is not a subclass of WidgetFactory\n";
}


if (
is_subclass_of($WF, 'WidgetFactory')) {
  echo
"yes, \$WF is a subclass of WidgetFactory\n";
} else {
  echo
"no, \$WF is not a subclass of WidgetFactory\n";
}


// usable only since PHP 5.0.3
if (is_subclass_of('WidgetFactory_Child', 'WidgetFactory')) {
  echo
"yes, WidgetFactory_Child is a subclass of WidgetFactory\n";
} else {
  echo
"no, WidgetFactory_Child is not a subclass of WidgetFactory\n";
}
?>

The above example will output:

yes, $WFC is a subclass of WidgetFactory
no, $WF is not a subclass of WidgetFactory
yes, WidgetFactory_Child is a subclass of WidgetFactory

See also get_class(), get_parent_class() and is_a().

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