php-doc-en/reference/csprng/functions/random-int.xml

<?xml version="1.0" encoding="utf-8"?>
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<refentry xml:id="function.random-int" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>random_int</refname>
  <refpurpose>Generates cryptographically secure pseudo-random integers</refpurpose>
 </refnamediv>

 <refsect1 role="description"><!-- {{{ -->
  &reftitle.description;
  <methodsynopsis role="procedural">
   <type>int</type><methodname>random_int</methodname>
   <methodparam><type>int</type><parameter>min</parameter></methodparam>
   <methodparam><type>int</type><parameter>max</parameter></methodparam>
  </methodsynopsis>
  <para>
   Generates cryptographic random integers that are suitable for use where unbiased results are critical
   (i.e. shuffling a Poker deck).
  </para>
  <para>
   The sources of random are as follows:
  </para>
  <itemizedlist>
   <listitem>
    <simpara>
     On Windows <function>CryptGenRandom</function> is used exclusively
    </simpara>
   </listitem>
   <listitem>
    <simpara>
     <function>arc4random_buf</function> is used if it is available (generally BSD specific)
    </simpara>
   </listitem>
   <listitem>
    <simpara>
     <filename>/dev/arandom</filename> is used where available
    </simpara>
   </listitem>
   <listitem>
    <simpara>
     <filename>/dev/urandom</filename> is used where none of the above is available
    </simpara>
   </listitem>
  </itemizedlist>
 </refsect1><!-- }}} -->

 <refsect1 role="parameters"><!-- {{{ -->
  &reftitle.parameters;
  <variablelist>
   <varlistentry>
    <term><parameter>min</parameter></term>
    <listitem>
     <para>
      The lowest value to be returned down to <constant>PHP_INT_MIN</constant>.
     </para>
    </listitem>
   </varlistentry>
   <varlistentry>
    <term><parameter>max</parameter></term>
    <listitem>
     <para>
      The highest value to be returned up to <constant>PHP_INT_MAX</constant>.
     </para>
    </listitem>
   </varlistentry>
  </variablelist>
 </refsect1><!-- }}} -->

 <refsect1 role="returnvalues"><!-- {{{ -->
  &reftitle.returnvalues;
  <para>
   Returns a crypto-secure random integer.
  </para>
 </refsect1><!-- }}} -->

 <refsect1 role="errors"><!-- {{{ -->
  &reftitle.errors;
  <para>
   Issues an <constant>E_WARNING</constant> and returns &false; when a sufficient source of randomness is unavailable.
  </para>
 </refsect1><!-- }}} -->

 <refsect1 role="examples"><!-- {{{ -->
  &reftitle.examples;
  <example xml:id="random-int.example.basic"><!-- {{{ -->
   <title><function>random-int</function> example</title>
   <programlisting role="php">
<![CDATA[
<?php
var_dump(random_int(100, 999));
var_dump(random_int(-1000, 0));
?>
]]>
   </programlisting>
   &example.outputs.similar;
   <screen>
<![CDATA[
int(248)
int(-898)
]]>
   </screen>
  </example><!-- }}} -->
 </refsect1><!-- }}} -->

 <refsect1 role="seealso"><!-- {{{ -->
  &reftitle.seealso;
  <simplelist>
   <member><function>random_bytes</function></member>
  </simplelist>
 </refsect1><!-- }}} -->

</refentry>

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