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https://github.com/sigmasternchen/php-doc-en
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4754397753
Document false and null return types Cf. <https://news-web.php.net/php.doc.cvs/17645>. git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@351729 c90b9560-bf6c-de11-be94-00142212c4b1
151 lines
3.8 KiB
XML
151 lines
3.8 KiB
XML
<?xml version="1.0" encoding="utf-8"?>
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<!-- $Revision$ -->
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<refentry xml:id="function.bcpowmod" xmlns="http://docbook.org/ns/docbook">
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<refnamediv>
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<refname>bcpowmod</refname>
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<refpurpose>Raise an arbitrary precision number to another, reduced by a specified modulus</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>bcpowmod</methodname>
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<methodparam><type>string</type><parameter>num</parameter></methodparam>
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<methodparam><type>string</type><parameter>exponent</parameter></methodparam>
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<methodparam><type>string</type><parameter>modulus</parameter></methodparam>
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<methodparam choice="opt"><type class="union"><type>int</type><type>null</type></type><parameter>scale</parameter><initializer>&null;</initializer></methodparam>
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</methodsynopsis>
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<para>
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Use the fast-exponentiation method to raise
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<parameter>num</parameter> to the power
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<parameter>exponent</parameter> with respect to the modulus
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<parameter>modulus</parameter>.
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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>num</parameter></term>
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<listitem>
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<para>
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The base, as an integral string (i.e. the scale has to be zero).
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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>exponent</parameter></term>
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<listitem>
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<para>
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The exponent, as an non-negative, integral string (i.e. the scale has to be zero).
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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>modulus</parameter></term>
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<listitem>
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<para>
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The modulus, as an integral string (i.e. the scale has to be zero).
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</para>
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</listitem>
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</varlistentry>
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&bc.scale.description;
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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 result as a string, or &false; if <parameter>modulus</parameter>
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is <literal>0</literal> or <parameter>exponent</parameter> is negative.
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</para>
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</refsect1>
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<refsect1 role="notes">
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&reftitle.notes;
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<note>
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<para>
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Because this method uses the modulus operation, numbers which are not
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positive integers may give unexpected results.
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</para>
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</note>
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</refsect1>
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<refsect1 role="changelog">
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&reftitle.changelog;
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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>8.0.0</entry>
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<entry>
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<parameter>scale</parameter> is now nullable.
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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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</refsect1>
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<refsect1 role="examples">
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&reftitle.examples;
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<para>
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The following two statements are functionally identical. The
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<function>bcpowmod</function> version however, executes in
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less time and can accept larger parameters.
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<informalexample>
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<programlisting role="php">
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<![CDATA[
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<?php
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$a = bcpowmod($x, $y, $mod);
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$b = bcmod(bcpow($x, $y), $mod);
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// $a and $b are equal to each other.
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?>
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]]>
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</programlisting>
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</informalexample>
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</para>
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</refsect1>
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<refsect1 role="seealso">
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&reftitle.seealso;
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<para>
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<simplelist>
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<member><function>bcpow</function></member>
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<member><function>bcmod</function></member>
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</simplelist>
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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:"~/.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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