LII. iconv Functions


This module contains an interface to iconv character set conversion facility. With this module, you can turn a string represented by a local character set into the one represented by another character set, which may be the Unicode character set. Supported character sets depend on the iconv implementation of your system. Note that the iconv function on some systems may not work as you expect. In such case, it'd be a good idea to install the GNU libiconv library. It will most likely end up with more consistent results.

Since PHP 5.0.0, this extension comes with various utility functions that help you to write multilingual scripts. Let's have a look at the following sections to explore the new features.


You will need nothing if the system you are using is one of the recent POSIX-compliant systems because standard C libraries that are supplied in them must provide iconv facility. Otherwise, you have to get the libiconv library installed in your system.


To use functions provided by this module, the PHP binary must be built with the following configure line: --with-iconv[=DIR].

Note to Windows Users: In order to enable this module on a Windows environment, you need to put a DLL file named iconv.dll or iconv-1.3.dll (prior to 4.2.1) which is bundled with the PHP/Win32 binary package into a directory specified by the PATH environment variable or one of the system directories of your Windows installation.

This module is part of PHP as of PHP 5 thus iconv.dll and php_iconv.dll is not needed anymore.


这些函数的行为受 php.ini 的影响。

表格 1. Iconv configuration options

iconv.input_encoding"ISO-8859-1"PHP_INI_ALLAvailable since PHP 4.0.5.
iconv.output_encoding"ISO-8859-1"PHP_INI_ALLAvailable since PHP 4.0.5.
iconv.internal_encoding"ISO-8859-1"PHP_INI_ALLAvailable since PHP 4.0.5.
有关 PHP_INI_* 常量进一步的细节与定义参见附录 G

注: Configuration option iconv.input_encoding is currently not used for anything.




Since PHP 4.3.0 it is possible to identify at runtime which iconv implementation is adopted by this extension.

表格 2. iconv constants

ICONV_IMPLstringThe implementation name
ICONV_VERSIONstringThe implementation version

注: Writing implementation-dependent scripts with these constants is strongly discouraged.

Since PHP 5.0.0, the following constants are also available:

表格 3. iconv constants available since PHP 5.0.0

ICONV_MIME_DECODE_STRICTintegerA bitmask used for iconv_mime_decode()
ICONV_MIME_DECODE_CONTINUE_ON_ERRORintegerA bitmask used for iconv_mime_decode()

iconv_get_encoding -- Retrieve internal configuration variables of iconv extension
iconv_mime_decode_headers --  Decodes multiple MIME header fields at once
iconv_mime_decode --  Decodes a MIME header field
iconv_mime_encode --  Composes a MIME header field
iconv_set_encoding -- Set current setting for character encoding conversion
iconv_strlen --  Returns the character count of string
iconv_strpos --  Finds position of first occurrence of a needle within a haystack
iconv_strrpos --  Finds the last occurrence of a needle within the specified range of haystack
iconv_substr --  Cut out part of a string
iconv -- Convert string to requested character encoding
ob_iconv_handler -- Convert character encoding as output buffer handler

add a note add a note User Contributed Notes
Fabian Ketchup
13-Sep-2006 09:00
// Simple file translation.

$FileToconvert = "menu.xml";
$FileConverted = "menu2.xml";

echo "Converting $FileToconvert ...";

file_put_contents($FileConverted, iconv("ISO-8859-1","UTF-8",file_get_contents($FileToconvert)));

echo "File converted in $FileConverted";
nod at mobi dot kz
17-Jul-2006 10:17
If you need convert string from Windows-1251 to 866. Some characters of 1251 haven't representation on DOS 866. For example, long dash -- chr(150) will be converted to 0, after that iconv finish his work and other charactes  will be skiped. Problem characters range in win1251 (128-159,163,165-167,169,171-174,177-182,187-190).

Use this:

//$text  -  input text in windows-1251
//$cout  -  output text in 866 (cp866, dos ru ascii)

for($i=0;$i<strlen($text);$i++) {
   if($ord>=192&&$ord<=239) $cout.=chr($ord-64);
   elseif($ord>=240&&$ord<=255) $cout.=chr($ord-16);
   elseif($ord==168) $cout.=chr(240);
   elseif($ord==184) $cout.=chr(241);
   elseif($ord==185) $cout.=chr(252);
   elseif($ord==150||$ord==151) $cout.=chr(45);
   elseif($ord==147||$ord==148||$ord==171||$ord==187) $cout.=chr(34);
   elseif($ord>=128&&$ord<=190) $i=$i; //
   else $cout.=chr($ord);
16-Mar-2006 08:22
There's one more special german character:  (sometimes displayed as )

so: case 159: $out .= "";break;
08-Nov-2005 04:05
But this is a very slow method to convert this:

// function to change german umlauts into ue, oe, etc.
function cv_input($str){

Better try this:
$tr = array(chr(xyz) => '', chr(160) => ' '); // Just a simple example, put all your characters in there
$string = strtr($string, $tr);
Christophe Lienert
27-Sep-2005 05:09
In addition to Godfather's note below, you may find this function useful just as well.

// function to change german umlauts into ue, oe, etc.
function cv_input($str){
     $out = "";
     for ($i = 0; $i<strlen($str);$i++){
           $ch= ord($str{$i});
               case 195: $out .= "";break;   
               case 164: $out .= "ae"; break;
               case 188: $out .= "ue"; break;
               case 182: $out .= "oe"; break;
               case 132: $out .= "Ae"; break;
               case 156: $out .= "Ue"; break;
               case 150: $out .= "Oe"; break;
               default : $out .= chr($ch) ;
     return $out;
The Godfather
15-Dec-2004 09:36
With this function you can translate the german Symbols from the character set UTF-8 in windows-1252.

function convert_text($str){
  $out = '';
  for ($i = 0; $i<strlen($str);$i++){
   $ch = ord($str{$i});
         case 252: $out .= chr(129);break; //u Umlaut
         case 220: $out .= chr(154);break;//U Umlaut
         case 228: $out .= chr(132);break;//a Umlaut 
         case 196: $out .= chr(142);break;//A Umlaut
         case 214: $out .= chr(153);break;//O Umlaut 
         case 246: $out .= chr(148);break;//o Umlaug
         case 223: $out .= chr(225);break;//SZ
         default : $out .= chr($ch) ;
  return $out;
tokiee at hotmail dot com
19-Aug-2004 04:40
iconv now has been built-in, at least in PHP >= 5.0.1 for win32. You don't have to modify php.ini for this. Actually you should not. And clearly, libiconv does not need to be installed.
24-Dec-2003 06:26
Windows users.

Personaly I leaved all php dlls in \php\dlls\ directory, just adding this path to my system path, and iconv.dll supplied with php 4.3.2 works fine, also leaving supplied php_iconv.dll in my \php\extensions\ directory. This was working fine with Apache and Omnihttpd server I use.

As soon I installed IIS on the same server, php complained about not finding php_iconv.dll in the extensions directory. In fact PHP with IIS loads all extensions in my \php\extensions directory correctly, except php_iconv.dll.
Although iconv.dll is in my system path, the only way to load php_iconv.dll was to copy iconv.dll file in \%winnt\system32 directory. With other servers, iconv.dll can be in anywhere in the system path.
07-Nov-2003 08:10
To windows users:

Download here iconv version 1.9.1:
14-Sep-2002 08:23
I'm not sure how recent version of
glibc 2.x Slackware 7.x/8.x comes with, but
it's very likely that it comes with glibc 2.2.x.
In that case, you don't have to bother at all to
install libiconv in /usr/local. iconv(3) in glibc 2.2.x
is very good (thanks to Ulrich Drepper and
Bruno Haible. the latter is the author of libiconv).
libiconv is very handy for those outdated/non-standard-compliant Unix
and non-Unix systems that don't have
sufficiently good iconv(3) in their C library.
elk at NOSPAMmodel-fx dot com
27-Jul-2002 12:07
If you use the libiconv library instead of the libc's iconv support, don't forget to use libiconv() instead of iconv()
elk at NOSPAMmodel-fx dot com
25-Jul-2002 11:39
To compile libiconv under Slackware 7.0 or 8.0 without errors (either with the apache module of PHP or the CGI version), you must specify the full path of the libiconv installation.

Exemple :