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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<sect1 xml:id="language.types.null">
<title>NULL</title>
<para>
The <type>null</type> type is PHP's unit type, i.e. it has only one value:
&null;.
</para>
<para>
Undefined, and <function>unset</function> variables will resolve to the
value &null;.
</para>
<sect2 xml:id="language.types.null.syntax">
<title>Syntax</title>
<para>
There is only one value of type <type>null</type>, and that is the
case-insensitive constant &null;.
</para>
<informalexample>
<programlisting role="php">
<![CDATA[
<?php
$var = NULL;
?>
]]>
</programlisting>
</informalexample>
</sect2>
<sect2 xml:id="language.types.null.casting">
<title>Casting to &null;</title>
<para>
&warn.deprecated.feature-7-2-0.removed-8-0-0;
</para>
<para>
Casting a variable to <type>null</type> using <literal>(unset) $var</literal>
will <emphasis>not</emphasis> remove the variable or unset its value.
It will only return a &null; value.
</para>
</sect2>
<sect2 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>is_null</function></member>
<member><function>unset</function></member>
</simplelist>
</para>
</sect2>
</sect1>
<!-- Keep this comment at the end of the file
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mode: sgml
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sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
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sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
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sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->
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