php-doc-en/reference/classobj/functions/is-a.xml

<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.10 $ -->
<refentry xml:id="function.is-a" xmlns="http://docbook.org/ns/docbook">
 <refnamediv>
  <refname>is_a</refname>
  <refpurpose>Checks if the object is of this class or has this class as one of its parents</refpurpose>
 </refnamediv>
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>bool</type><methodname>is_a</methodname>
   <methodparam><type>object</type><parameter>object</parameter></methodparam>
   <methodparam><type>string</type><parameter>class_name</parameter></methodparam>
  </methodsynopsis>
  <para>
   Checks if the given <parameter>object</parameter> is of this class or has
   this class as one of its parents.
  </para>
  <note>
   <para>
    The <function>is_a</function> function is deprecated as of PHP 5 in
    favor of the <link linkend="language.operators.type">instanceof</link>
    type operator.
   </para>
  </note>
 </refsect1>
 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>object</parameter></term>
     <listitem>
      <para>
       The tested object
      </para>
     </listitem>
    </varlistentry>
    <varlistentry>
     <term><parameter>class_name</parameter></term>
     <listitem>
      <para>
       The class name
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>
 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns &true; if the object is of this class or has this class as one of
   its parents, &false; otherwise.
  </para>
 </refsect1>
 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>is_a</function> example</title>
    <programlisting role="php">
<![CDATA[
<?php
// define a class
class WidgetFactory
{
  var $oink = 'moo';
}

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

if (is_a($WF, 'WidgetFactory')) {
  echo "yes, \$WF is still a WidgetFactory\n";
}
?>
]]>
    </programlisting>
   </example>
   <example>
    <title>Using the <emphasis>instanceof</emphasis> operator in PHP 5</title>
    <programlisting role="php">
<![CDATA[
<?php
if ($WF instanceof WidgetFactory) {
    echo 'Yes, $WF is a WidgetFactory';
}
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>
 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>get_class</function></member>
    <member><function>get_parent_class</function></member>
    <member><function>is_subclass_of</function></member>
   </simplelist>
  </para>
 </refsect1>
</refentry>

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