php-doc-en/reference/network/functions/ip2long.xml

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<refentry xml:id="function.ip2long" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
 <refnamediv>
  <refname>ip2long</refname>
  <refpurpose>Converts a string containing an (IPv4) Internet Protocol dotted address into a long integer</refpurpose>
 </refnamediv>
 
 <refsect1 role="description">
  &reftitle.description;
  <methodsynopsis>
   <type>int</type><methodname>ip2long</methodname>
   <methodparam><type>string</type><parameter>ip_address</parameter></methodparam>
  </methodsynopsis>
  <para>
   The function <function>ip2long</function> generates a long integer
   representation of IPv4 Internet network address from its Internet
   standard format (dotted string) representation. 
  </para>
  <para>
   <function>ip2long</function> will also work with non-complete IP
   addresses. Read <link xlink:href="&url.ip2long.tech;">&url.ip2long.tech;</link>
   for more info.
  </para>
 </refsect1>

 <refsect1 role="parameters">
  &reftitle.parameters;
  <para>
   <variablelist>
    <varlistentry>
     <term><parameter>ip_address</parameter></term>
     <listitem>
      <para>
       A standard format address.
      </para>
     </listitem>
    </varlistentry>
   </variablelist>
  </para>
 </refsect1>

 <refsect1 role="returnvalues">
  &reftitle.returnvalues;
  <para>
   Returns the long integer or &false; if <parameter>ip_address</parameter>
   is invalid.
  </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>5.5.0</entry>
       <entry>
        Prior to this version, on Windows <function>ip2long</function> would sometimes return
        a valid number even if passed a value which was not an (IPv4) Internet Protocol
        dotted address.
       </entry>
      </row>
      <row>
       <entry>5.2.10</entry>
       <entry>
        Prior to this version, <function>ip2long</function> would sometimes return
        a valid number even if passed a value which was not an (IPv4) Internet Protocol
        dotted address.
       </entry>
      </row>
     </tbody>
    </tgroup>
   </informaltable>
  </para>
 </refsect1>

 <refsect1 role="examples">
  &reftitle.examples;
  <para>
   <example>
    <title><function>ip2long</function> Example</title>
    <programlisting role="php">
<![CDATA[
<?php
$ip = gethostbyname('www.example.com');
$out = "The following URLs are equivalent:<br />\n";
$out .= 'http://www.example.com/, http://' . $ip . '/, and http://' . sprintf("%u", ip2long($ip)) . "/<br />\n";
echo $out;
?>
]]>
    </programlisting>
   </example>
  </para>
  <para>
   <example>
    <title>Displaying an IP address</title>
    <para>
     This second example shows how to print a converted address with the
     <function>printf</function> function:
    </para>
    <programlisting role="php">
<![CDATA[
<?php
$ip   = gethostbyname('www.example.com');
$long = ip2long($ip);

if ($long == -1 || $long === FALSE) {
    echo 'Invalid IP, please try again';
} else {
    echo $ip   . "\n";            // 192.0.34.166
    echo $long . "\n";            // 3221234342 (-1073732954 on 32-bit systems, due to integer overflow)
    printf("%u\n", ip2long($ip)); // 3221234342
}
?>
]]>
    </programlisting>
   </example>
  </para>
 </refsect1>

 <refsect1 role="notes">
  &reftitle.notes;
  <note>
   <para>
    Because PHP's <type>integer</type> type is signed, and many IP addresses
    will result in negative integers on 32-bit architectures, you need to use
    the "%u" formatter of <function>sprintf</function> or
    <function>printf</function> to get the string representation of the
    unsigned IP address.
   </para>
  </note>
  <note>
   <para>
    <function>ip2long</function> will return &false; for the IP
    <literal>255.255.255.255</literal> in PHP 5 &lt;= 5.0.2, and <literal>-1</literal>
    on 64-bits systems in PHP 5 &lt;=5.2.4. It was fixed in
    PHP 5.2.5 where it returns <literal>4294967295</literal>. 32-bit systems
    will return <literal>-1</literal> due to the integer value overflowing.    
   </para>
  </note>
 </refsect1>

 <refsect1 role="seealso">
  &reftitle.seealso;
  <para>
   <simplelist>
    <member><function>long2ip</function></member>
    <member><function>sprintf</function></member>
   </simplelist>
  </para>
 </refsect1>

</refentry>

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