mirror of
https://github.com/sigmasternchen/php-doc-en
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03b85439a5
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@133985 c90b9560-bf6c-de11-be94-00142212c4b1
76 lines
2.1 KiB
XML
76 lines
2.1 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision: 1.8 $ -->
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<!-- splitted from ./en/functions/misc.xml, last change in rev 1.2 -->
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<refentry id="function.defined">
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<refnamediv>
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<refname>defined</refname>
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<refpurpose>
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Checks whether a given named constant exists
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</refpurpose>
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</refnamediv>
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<refsect1>
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<title>Description</title>
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<methodsynopsis>
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<type>bool</type><methodname>defined</methodname>
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<methodparam><type>string</type><parameter>name</parameter></methodparam>
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</methodsynopsis>
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<para>
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Returns &true; if the named constant given by
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<parameter>name</parameter> has been defined,
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&false; otherwise.
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</para>
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<para>
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<example>
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<title>Checking Constants</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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/* Note the use of quotes, this is important. This example is checking
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* if the string 'CONSTANT' is the name of a constant named CONSTANT */
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if (defined('CONSTANT')) {
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echo CONSTANT;
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}
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?>
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]]>
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</programlisting>
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</example>
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</para>
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<note>
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<para>
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If you want to see if a variable exists, use
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<function>isset</function> as <function>defined</function> only
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applies to <link linkend="language.constants">constants</link>.
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If you want to see if a function exists, use
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<function>function_exists</function>.
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</para>
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</note>
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<para>
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See also <function>define</function>,
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<function>constant</function>,
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<function>get_defined_constants</function>,
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<function>function_exists</function>, and the section on
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<link linkend="language.constants">Constants</link>.
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</para>
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</refsect1>
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</refentry>
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<!-- Keep this comment at the end of the file
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Local variables:
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mode: sgml
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sgml-omittag:t
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sgml-shorttag:t
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sgml-minimize-attributes:nil
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sgml-always-quote-attributes:t
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sgml-indent-step:1
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sgml-indent-data:t
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indent-tabs-mode:nil
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sgml-parent-document:nil
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sgml-default-dtd-file:"../../../../manual.ced"
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sgml-exposed-tags:nil
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sgml-local-catalogs:nil
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sgml-local-ecat-files:nil
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End:
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vim600: syn=xml fen fdm=syntax fdl=2 si
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vim: et tw=78 syn=sgml
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vi: ts=1 sw=1
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-->
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