1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147
|
<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision: 323895 $ -->
<refentry xml:id="function.pow" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>pow</refname>
<refpurpose>Exponential expression</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>number</type><methodname>pow</methodname>
<methodparam><type>number</type><parameter>base</parameter></methodparam>
<methodparam><type>number</type><parameter>exp</parameter></methodparam>
</methodsynopsis>
<para>
Returns <parameter>base</parameter> raised to the power of
<parameter>exp</parameter>.
</para>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>base</parameter></term>
<listitem>
<para>
The base to use
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>exp</parameter></term>
<listitem>
<para>
The exponent
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
<parameter>base</parameter> raised to the power of <parameter>exp</parameter>.
If both arguments are non-negative integers and the result can be represented
as an integer, the result will be returned with <type>integer</type> type,
otherwise it will be returned as a <type>float</type>.
</para>
</refsect1>
<refsect1 role="changelog">
&reftitle.changelog;
<para>
<informaltable>
<tgroup cols="2">
<thead>
<row>
<entry>&Version;</entry>
<entry>&Description;</entry>
</row>
</thead>
<tbody>
<row>
<entry>4.2.0</entry>
<entry>
No warning is emitted on errors, even if the value can't be computed.
</entry>
</row>
<row>
<entry>4.0.6</entry>
<entry>
The function will now return <type>integer</type> results if possible,
before this it always returned a <type>float</type> result. For older
versions, you may receive a bogus result for complex numbers.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title>Some examples of <function>pow</function></title>
<programlisting role="php">
<![CDATA[
<?php
var_dump(pow(2, 8)); // int(256)
echo pow(-1, 20); // 1
echo pow(0, 0); // 1
echo pow(-1, 5.5); // PHP >4.0.6 NAN
echo pow(-1, 5.5); // PHP <=4.0.6 1.#IND
?>
]]>
</programlisting>
</example>
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
<note>
<para>
This function will convert all input to a number, even non-scalar values,
which could lead to <literal>weird</literal> results.
</para>
</note>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>exp</function></member>
<member><function>sqrt</function></member>
<member><function>bcpow</function></member>
<member><function>gmp_pow</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
indent-tabs-mode:nil
sgml-parent-document:nil
sgml-default-dtd-file:"~/.phpdoc/manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
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
-->
|