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    mb_regex_encoding

    (PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

    mb_regex_encoding — Set/Get character encoding for multibyte regex

    Description

    function mb_regex_encoding(?string $encoding = null): string|bool

    Set/Get character encoding for a multibyte regex.

    Parameters

    encoding

    The encoding parameter is the character encoding. If it is omitted or null, the internal character encoding value will be used.

    Return Values

    If encoding is set, then Returns true on success or false on failure. In this case, the internal character encoding is NOT changed. If encoding is omitted, then the current character encoding name for a multibyte regex is returned.

    Errors/Exceptions

    As of PHP 8.0.0, a ValueError is thrown if encoding is an invalid encoding. Prior to PHP 8.0.0, an E_WARNING was emitted instead.

    Changelog

    Version Description
    8.0.0 encoding is nullable now.
    8.0.0 Now throws a ValueError if encoding is an invalid encoding. Previously, an E_WARNING was emitted and false was returned.

    See Also

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    User Contributed Notes 4 notes

    up
    4
    GerryH
    9 years ago
    mb_ereg functionality is provided via Oniguruma RegEx library and not via PCRE. mb_regex_encoding() does only support a subset of encoding names, compared to mb_list_encodings() and mb_encoding_aliases().
Currently the following names are supported (case-insensitive):

UCS-4
UCS-4LE
UTF-32
UTF-32BE
UTF-32LE
UTF-16
UTF-16BE
UTF-16LE
UTF-8
utf8
ASCII
US-ASCII
EUC-JP
eucJP
x-euc-jp
SJIS
eucJP-win
SJIS-win
CP932
MS932
Windows-31J
ISO-8859-1
ISO-8859-2
ISO-8859-3
ISO-8859-4
ISO-8859-5
ISO-8859-6
ISO-8859-7
ISO-8859-8
ISO-8859-9
ISO-8859-10
ISO-8859-13
ISO-8859-14
ISO-8859-15
ISO-8859-16
EUC-CN
EUC_CN
eucCN
gb2312
EUC-TW
EUC_TW
eucTW
BIG-5
CN-BIG5
BIG-FIVE
BIGFIVE
EUC-KR
EUC_KR
eucKR
KOI8-R
KOI8R

The list is a mixture of base names and aliases and applies to PHP 5.4.45 (Oniguruma lib v4.7.1), PHP 5.6.31 (v5.9.5), PHP 7.0.22 (v5.9.6) and PHP 7.1.8 (v5.9.6). Be aware of the inconsistency: mb_regex_encoding() accepts for example the base name 'UTF-8' and its only alias 'utf8', but it does not accept aliases 'utf16', 'utf32' or 'latin1'.

Additionally note, that the informal name/alias 'latin9' for ISO/IEC 8859-15:1999 (including the Euro sign on 0xA4) is also not known by mb_list_encodings(). It can only be adressed as 'ISO-8859-15' or 'ISO_8859-15' and for mb_regex_encoding() solely as 'ISO-8859-15'.
    up
    3
    php dot net at phor dot net
    16 years ago
    Beware, mb_regex_encoding does not support the same set of encodings as listed in mb_list_encodings.php

Example:

<?php
mb_internal_encoding('CP936');
mb_regex_encoding('CP936'); # this line produces an error
 ?>
    up
    -1
    code at roberthairgrove dot com
    9 years ago
    mb_regex_encoding does not recognize CP1252 or Windows-1252 as valid encodings, although they are in the list generated by mb_list_encodings.

ISO-8859-1 (AKA "Latin-1") is supported, but it's not the same as the Windows variety of Latin-1.
    up
    -4
    Anonymous
    17 years ago
    To change algo the regex_encodign
<?php
echo "current mb_internal_encoding: ".mb_internal_encoding()."<br />";
echo "changing mb_internal_encoding to UTF-8<br />";
mb_internal_encoding("UTF-8"); 
echo "new mb_internal_encoding: ".mb_internal_encoding()."<br />";

echo "current mb_regex_encoding: ".mb_regex_encoding()."<br />";
echo "changing mb_regex_encoding to UTF-8<br />";
mb_regex_encoding('UTF-8');
echo "new mb_regex_encoding: ".mb_regex_encoding()."<br />";
?>
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