mb_regex_encoding

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

mb_regex_encoding — Set/Get character encoding for multibyte regex

说明

mixed mb_regex_encoding ([ string $encoding = mb_regex_encoding() ] )

Set/Get character encoding for a multibyte regex.

参数

encoding

encoding 参数为字符编码。如果省略，则使用内部字符编码。

返回值

If encoding is set, then 成功时返回 TRUE， 或者在失败时返回 FALSE。 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.

更新日志

版本 说明
5.6.0 Default encoding is changed to UTF-8. It was EUC-JP Previously.

参见

User Contributed Notes

GerryH 16-Sep-2017 10:49
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'.
code at roberthairgrove dot com 04-Aug-2017 07:19
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.
php dot net at phor dot net 31-Aug-2010 10:40
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
 ?>
Anonymous 28-Jun-2009 07:07
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 />";
?>
zl at zl dot hu 29-May-2009 03:05
Return values vary in setting and getting:

<?php
  echo mb_regex_encoding();
  // returns encoding name as a string
?>

<?php
  echo mb_regex_encoding("UTF-8");
  // returns true (success) of false as a boolean
?>