ConFoo 2025

    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

    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.

    Changelog

    Version Description
    8.0.0 encoding is nullable now.

    See Also

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    User Contributed Notes 4 notes

    up
    3
    GerryH
    7 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
    4
    php dot net at phor dot net
    14 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
    0
    code at roberthairgrove dot com
    7 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
    15 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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