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<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->
<refentry xml:id="function.rand" xmlns="http://docbook.org/ns/docbook">
<refnamediv>
<refname>rand</refname>
<refpurpose>Generate a random integer</refpurpose>
</refnamediv>
<refsect1 role="description">
&reftitle.description;
<methodsynopsis>
<type>int</type><methodname>rand</methodname>
<void/>
</methodsynopsis>
<methodsynopsis>
<type>int</type><methodname>rand</methodname>
<methodparam><type>int</type><parameter>min</parameter></methodparam>
<methodparam><type>int</type><parameter>max</parameter></methodparam>
</methodsynopsis>
<simpara>
If called without the optional <parameter>min</parameter>,
<parameter>max</parameter> arguments <function>rand</function>
returns a pseudo-random integer between 0 and
<function>getrandmax</function>. If you want a random number
between 5 and 15 (inclusive), for example, use <literal>rand(5,
15)</literal>.
</simpara>
&caution.cryptographically-insecure;
<note>
<simpara>
Prior to PHP 7.1.0, <function>getrandmax</function> was only 32767 on some
platforms (such as Windows). If you require a range larger than 32767, specifying
<parameter>min</parameter> and <parameter>max</parameter> will allow
you to create a range larger than this, or consider using
<function>mt_rand</function> instead.
</simpara>
</note>
<note><simpara>As of PHP 7.1.0, <function>rand</function> uses the same
random number generator as <function>mt_rand</function>. To preserve
backwards compatibility <function>rand</function> allows
<parameter>max</parameter> to be smaller than <parameter>min</parameter>
as opposed to returning &false; as <function>mt_rand</function>.</simpara>
</note>
</refsect1>
<refsect1 role="parameters">
&reftitle.parameters;
<para>
<variablelist>
<varlistentry>
<term><parameter>min</parameter></term>
<listitem>
<para>
The lowest value to return (default: 0)
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><parameter>max</parameter></term>
<listitem>
<para>
The highest value to return (default: <function>getrandmax</function>)
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</refsect1>
<refsect1 role="returnvalues">
&reftitle.returnvalues;
<para>
A pseudo random value between <parameter>min</parameter>
(or 0) and <parameter>max</parameter> (or <function>getrandmax</function>, inclusive).
</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>7.2.0</entry>
<entry>
<function>rand</function> <link linkend="migration72.incompatible.rand-mt_rand-output">has received a bug fix</link> for a modulo bias bug. This means that sequences generated with a specific seed may differ from PHP 7.1 on 64-bit machines.
</entry>
</row>
<row>
<entry>7.1.0</entry>
<entry>
<function>rand</function> <link linkend="migration71.incompatible.rand-srand-aliases">has been made</link> an alias of <function>mt_rand</function>.
</entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</refsect1>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title><function>rand</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
echo rand(), "\n";
echo rand(), "\n";
echo rand(5, 15), "\n";
?>
]]>
</programlisting>
&example.outputs.similar;
<screen>
<![CDATA[
7771
22264
11
]]>
</screen>
</example>
</para>
</refsect1>
<refsect1 role="notes">
&reftitle.notes;
<warning>
<para>
<parameter>min</parameter> <parameter>max</parameter> range must
be within the range <function>getrandmax</function>. i.e. (<parameter>max</parameter> -
<parameter>min</parameter>) <= <function>getrandmax</function>
Otherwise, <function>rand</function> may return poor-quality random numbers.
</para>
</warning>
</refsect1>
<refsect1 role="seealso">
&reftitle.seealso;
<para>
<simplelist>
<member><function>srand</function></member>
<member><function>getrandmax</function></member>
<member><function>mt_rand</function></member>
<member><function>random_int</function></member>
<member><function>random_bytes</function></member>
</simplelist>
</para>
</refsect1>
</refentry>
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