php man page for is_a

IS_A(3) 								 1								   IS_A(3)

is_a - Checks if the object is of this class or has this class as one of its parents

SYNOPSIS
       bool is_a FALSE (object	$object, string  $class_name, [bool  $allow_string])

DESCRIPTION
	Checks if the given $object is of this class or has this class as one of its parents.

PARAMETERS
	      o $object
		- The tested object

	      o $class_name
		- The class name

	      o $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.

RETURN VALUES
	Returns TRUE if the object is of this class or has this class as one of its parents, FALSE otherwise.

CHANGELOG
       +--------+---------------------------------------------------+
       |Version |						    |
       |	|						    |
       |	|		     Description		    |
       |	|						    |
       +--------+---------------------------------------------------+
       | 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.		    |
       |	|						    |
       +--------+---------------------------------------------------+
EXAMPLES
       Example #1

	      is_a(3) 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
";
	      }
	      ?>

       Example #2

	      Using the instanceof operator in PHP 5

	      <?php
	      if ($WF instanceof WidgetFactory) {
		  echo 'Yes, $WF is a WidgetFactory';
	      }
	      ?>

SEE ALSO
       get_class(3), get_parent_class(3), is_subclass_of(3).

PHP Documentation Group 														   IS_A(3)