mirror of
https://github.com/sigmasternchen/php-doc-en
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1634a88641
git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@330340 c90b9560-bf6c-de11-be94-00142212c4b1
81 lines
2.6 KiB
XML
81 lines
2.6 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<book xml:id="book.ctype" xmlns="http://docbook.org/ns/docbook">
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<?phpdoc extension-membership="bundled" ?>
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<title>Character type checking</title>
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<titleabbrev>Ctype</titleabbrev>
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<preface xml:id="intro.ctype">
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&reftitle.intro;
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<para>
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The functions provided by this extension check whether a character
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or string falls into a certain character class according to the
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current locale (see also <function>setlocale</function>).
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</para>
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<para>
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When called with an integer argument these functions
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behave exactly like their C counterparts from
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<filename>ctype.h</filename>.
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It means that if you pass an integer smaller than 256 it will use the
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ASCII value of it to see if it fits in the specified range (digits are in
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0x30-0x39). If the number is between -128 and -1 inclusive then 256 will
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be added and the check will be done on that.
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</para>
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<para>
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When called with a string argument they will check
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every character in the string and will only return
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&true; if every character in the string matches the
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requested criteria. When called with an empty string
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the result will always be &true; in PHP < 5.1 and &false; since 5.1.
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</para>
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<para>
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Passing anything else but a string or integer will
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return &false; immediately.
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</para>
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<para>
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It should be noted that ctype functions are always preferred over
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regular expressions, and even to some equivalent <literal>"str_*"</literal> and <literal>"is_*"</literal> functions.
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This is because of the fact that ctype uses a native C library and thus
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processes significantly faster.
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</para>
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<note>
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<para>
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These functions are not related to the Python "ctypes" library at all.
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The extension name stems from the <filename>ctype.h</filename> C header
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file that their C equivalents are defined in.
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</para>
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<para>
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This extension also predates Python "ctypes" so any confusion
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caused by this naming is hardly our fault ...
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</para>
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</note>
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</preface>
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&reference.ctype.setup;
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&reference.ctype.constants;
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&reference.ctype.reference;
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</book>
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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:"~/.phpdoc/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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