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<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.8 $ -->
<!-- splitted from ./en/functions/math.xml, last change in rev 1.2 -->
<refentry id="function.srand">
<refnamediv>
<refname>srand</refname>
<refpurpose>Seed the random number generator</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<methodsynopsis>
<type>void</type><methodname>srand</methodname>
<methodparam choice="opt"><type>int</type><parameter>seed</parameter></methodparam>
</methodsynopsis>
<para>
Seeds the random number generator with <parameter>seed</parameter>.
Since PHP 4.2.0, the <parameter>seed</parameter>
becomes optional and defaults to a random value if omitted.
</para>
<para>
<example>
<title><function>srand</function> example</title>
<programlisting role="php">
<![CDATA[
<?php
// seed with microseconds
function make_seed()
{
list($usec, $sec) = explode(' ', microtime());
return (float) $sec + ((float) $usec * 100000);
}
srand(make_seed());
$randval = rand();
?>
]]>
</programlisting>
</example>
</para>
¬e.randomseed;
<simpara>
See also:
<function>rand</function>,
<function>getrandmax</function>, and
<function>mt_srand</function>.
</simpara>
</refsect1>
</refentry>
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