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https://github.com/sigmasternchen/php-doc-en
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c030e2adf7
- All id attributes are now xml:id - Add docbook namespace to all root elements - Replace <ulink /> with <link xlink:href /> - Minor markup fixes here and there git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@238160 c90b9560-bf6c-de11-be94-00142212c4b1
142 lines
3.6 KiB
XML
142 lines
3.6 KiB
XML
<?xml version="1.0" encoding="iso-8859-1"?>
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<!-- $Revision: 1.12 $ -->
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<refentry xml:id="function.uniqid" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>uniqid</refname>
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<refpurpose>Generate a unique ID</refpurpose>
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</refnamediv>
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<refsect1 role="description">
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&reftitle.description;
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<methodsynopsis>
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<type>string</type><methodname>uniqid</methodname>
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<methodparam choice="opt"><type>string</type><parameter>prefix</parameter></methodparam>
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<methodparam choice="opt"><type>bool</type><parameter>more_entropy</parameter></methodparam>
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</methodsynopsis>
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<para>
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Gets a prefixed unique identifier based on the current time in
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microseconds.
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</para>
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</refsect1>
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<refsect1 role="parameters">
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&reftitle.parameters;
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<para>
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<variablelist>
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<varlistentry>
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<term><parameter>prefix</parameter></term>
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<listitem>
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<para>
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Can be useful, for instance, if you generate identifiers
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simultaneously on several hosts that might happen to generate the
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identifier at the same microsecond.
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</para>
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<para>
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With an empty <parameter>prefix</parameter>, the returned string will
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be 13 characters long. If <parameter>more_entropy</parameter> is
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&true;, it will be 23 characters.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><parameter>more_entropy</parameter></term>
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<listitem>
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<para>
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If set to &true;, <function>uniqid</function> will add additional
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entropy (using the combined linear congruential generator) at the end
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of the return value, which should make the results more unique.
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</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsect1>
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<refsect1 role="returnvalues">
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&reftitle.returnvalues;
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<para>
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Returns the unique identifier, as a string.
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</para>
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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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If you need a unique identifier or token and you intend to give
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out that token to the user via the network (i.e. session cookies),
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it is recommended that you use something along these lines:
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</para>
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<para>
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This will create a 32 character identifier (a 128 bit hex number)
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that is extremely difficult to predict.
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<example>
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<title><function>uniqid</function> Example</title>
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<programlisting role="php">
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<![CDATA[
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<?php
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// no prefix
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// works only in PHP 5 and later versions
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$token = md5(uniqid());
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// better, difficult to guess
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$better_token = md5(uniqid(rand(), true));
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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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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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<para>
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<informaltable>
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<tgroup cols="2">
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<thead>
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<row>
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<entry>&Version;</entry>
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<entry>&Description;</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry>5.0.0</entry>
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<entry>
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The <parameter>prefix</parameter> parameter was made optional.
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</entry>
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</row>
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<row>
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<entry>4.3.1</entry>
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<entry>
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The limit of 114 characters long for <parameter>prefix</parameter>
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was raised.
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</entry>
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</row>
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</tbody>
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</tgroup>
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</informaltable>
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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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