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## Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

mbstring configuration options
Name | Default | Changeable | Changelog
--- | --- | --- | ---
mbstring.language | "neutral" | PHP_INI_ALL | Available since PHP 4.3.0. PHP_INI_PERDIR in PHP <= 5.2.6
mbstring.detect_order | NULL | PHP_INI_ALL | Available since PHP 4.0.6.
mbstring.http_input | "pass" | PHP_INI_ALL | Available since PHP 4.0.6. Deprecated in PHP 5.6.0.
mbstring.http_output | "pass" | PHP_INI_ALL | Available since PHP 4.0.6. Deprecated in PHP 5.6.0.
mbstring.internal_encoding | NULL | PHP_INI_ALL | Available since PHP 4.0.6. Deprecated in PHP 5.6.0.
mbstring.script_encoding | NULL | PHP_INI_ALL | Available since PHP 4.3.0. Removed in PHP 5.4.0. Use zend.script_encoding instead.
mbstring.substitute_character | NULL | PHP_INI_ALL | Available since PHP 4.0.6.
mbstring.func_overload | "0" | PHP_INI_SYSTEM | PHP_INI_PERDIR from PHP 4.3 to 5.2.6, otherwise PHP_INI_SYSTEM. Available since PHP 4.2.0.
mbstring.encoding_translation | "0" | PHP_INI_PERDIR | Available since PHP 4.3.0.
mbstring.strict_detection | "0" | PHP_INI_ALL | Available since PHP 5.1.2.

For further details and definitions of the PHP_INI_* modes, see the Where a configuration setting may be set.

Here's a short explanation of the configuration directives.

`mbstring.language` string

  The default national language setting (NLS) used in mbstring. Note that this option automagically defines mbstring.internal_encoding and mbstring.internal_encoding should be placed after mbstring.language in php.ini

`mbstring.encoding_translation` boolean

  Enables the transparent character encoding filter for the incoming HTTP queries, which performs detection and conversion of the input encoding to the internal character encoding.

`mbstring.internal_encoding` string
  Warning

  This feature has been DEPRECATED as of PHP 5.6.0. Relying on this feature is highly discouraged.

  Defines the default internal character encoding.

  PHP 5.6 and later users should leave this empty and set `default_charset` instead.

`mbstring.http_input` string
  Warning

  This feature has been DEPRECATED as of PHP 5.6.0. Relying on this feature is highly discouraged.

  Defines the default HTTP input character encoding.

  PHP 5.6 and later users should leave this empty and set `default_charset` instead.

`mbstring.http_output` string
  Warning

  This feature has been DEPRECATED as of PHP 5.6.0. Relying on this feature is highly discouraged.

  Defines the default HTTP output character encoding (output will be converted from the internal encoding to the HTTP output encoding upon output).

  PHP 5.6 and later users should leave this empty and set `default_charset` instead.

`mbstring.detect_order` string

  Defines default character code detection order. See also mb_detect_order().

`mbstring.substitute_character` string

  Defines character to substitute for invalid character encoding.

`mbstring.func_overload` string

  Overloads a set of single byte functions by the mbstring counterparts. See Function overloading for more information.

  This setting can only be changed from the php.ini file.

`mbstring.strict_detection` boolean

  Enables the strict encoding detection.

According to the » HTML 4.01 specification, Web browsers are allowed to encode a form being submitted with a character encoding different from the one used for the page. See mb_http_input() to detect character encoding used by browsers.

Although popular browsers are capable of giving a reasonably accurate guess to the character encoding of a given HTML document, it would be better to set the charset parameter in the Content-Type HTTP header to the appropriate value by header() or default_charset ini setting.

Example #1 php.ini setting examples

    ; Set default language
    mbstring.language        = Neutral; Set default language to Neutral(UTF-8) (default)
    mbstring.language        = English; Set default language to English
    mbstring.language        = Japanese; Set default language to Japanese

    ;; Set default internal encoding
    ;; Note: Make sure to use character encoding works with PHP
    mbstring.internal_encoding    = UTF-8  ; Set internal encoding to UTF-8

    ;; HTTP input encoding translation is enabled.
    mbstring.encoding_translation = On

    ;; Set default HTTP input character encoding
    ;; Note: Script cannot change http_input setting.
    mbstring.http_input           = pass    ; No conversion.
    mbstring.http_input           = auto    ; Set HTTP input to auto
                                    ; "auto" is expanded according to mbstring.language
    mbstring.http_input           = SJIS    ; Set HTTP input to SJIS
    mbstring.http_input           = UTF-8,SJIS,EUC-JP ; Specify order

    ;; Set default HTTP output character encoding
    mbstring.http_output          = pass    ; No conversion
    mbstring.http_output          = UTF-8   ; Set HTTP output encoding to UTF-8

    ;; Set default character encoding detection order
    mbstring.detect_order         = auto    ; Set detect order to auto
    mbstring.detect_order         = ASCII,JIS,UTF-8,SJIS,EUC-JP ; Specify order

    ;; Set default substitute character
    mbstring.substitute_character = 12307   ; Specify Unicode value
    mbstring.substitute_character = none    ; Do not print character
    mbstring.substitute_character = long    ; Long Example: U+3000,JIS+7E7E

Example #2 php.ini setting for EUC-JP users

    ;; Disable Output Buffering
    output_buffering      = Off

    ;; Set HTTP header charset
    default_charset       = EUC-JP

    ;; Set default language to Japanese
    mbstring.language = Japanese

    ;; HTTP input encoding translation is enabled.
    mbstring.encoding_translation = On

    ;; Set HTTP input encoding conversion to auto
    mbstring.http_input   = auto

    ;; Convert HTTP output to EUC-JP
    mbstring.http_output  = EUC-JP

    ;; Set internal encoding to EUC-JP
    mbstring.internal_encoding = EUC-JP

    ;; Do not print invalid characters
    mbstring.substitute_character = none

Example #3 php.ini setting for SJIS users

    ;; Enable Output Buffering
    output_buffering     = On

    ;; Set mb_output_handler to enable output conversion
    output_handler       = mb_output_handler

    ;; Set HTTP header charset
    default_charset      = Shift_JIS

    ;; Set default language to Japanese
    mbstring.language = Japanese

    ;; Set http input encoding conversion to auto
    mbstring.http_input  = auto

    ;; Convert to SJIS
    mbstring.http_output = SJIS

    ;; Set internal encoding to EUC-JP
    mbstring.internal_encoding = EUC-JP

    ;; Do not print invalid characters
    mbstring.substitute_character = none

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