multibyte(3) BSD Library Functions Manual multibyte(3)
NAME
multibyte -- multibyte and wide character manipulation functions
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <limits.h>
#include <stdlib.h>
#include <wchar.h>
DESCRIPTION
The basic elements of some written natural languages, such as Chinese,
cannot be represented uniquely with single C chars. The C standard sup-
ports two different ways of dealing with extended natural language encod-
ings: wide characters and multibyte characters. Wide characters are an
internal representation which allows each basic element to map to a sin-
gle object of type wchar_t. Multibyte characters are used for input and
output and code each basic element as a sequence of C chars. Individual
basic elements may map into one or more (up to MB_LEN_MAX) bytes in a
multibyte character.
The current locale (setlocale(3)) governs the interpretation of wide and
multibyte characters. The locale category LC_CTYPE specifically controls
this interpretation. The wchar_t type is wide enough to hold the largest
value in the wide character representations for all locales.
Multibyte strings may contain `shift' indicators to switch to and from
particular modes within the given representation. If explicit bytes are
used to signal shifting, these are not recognized as separate characters
but are lumped with a neighboring character. There is always a distin-
guished `initial' shift state. Some functions (e.g., mblen(3), mbtowc(3)
and wctomb(3)) maintain static shift state internally, whereas others
store it in an mbstate_t object passed by the caller. Shift states are
undefined after a call to setlocale(3) with the LC_CTYPE or LC_ALL cate-
gories.
For convenience in processing, the wide character with value 0 (the null
wide character) is recognized as the wide character string terminator,
and the character with value 0 (the null byte) is recognized as the
multibyte character string terminator. Null bytes are not permitted
within multibyte characters.
The C library provides the following functions for dealing with multibyte
characters:
Function Description
mblen(3) get number of bytes in a character
mbrlen(3) get number of bytes in a character (restartable)
mbrtowc(3) convert a character to a wide-character code (restartable)
mbsrtowcs(3) convert a character string to a wide-character string
(restartable)
mbstowcs(3) convert a character string to a wide-character string
mbtowc(3) convert a character to a wide-character code
wcrtomb(3) convert a wide-character code to a character (restartable)
wcstombs(3) convert a wide-character string to a character string
wcsrtombs(3) convert a wide-character string to a character string
(restartable)
wctomb(3) convert a wide-character code to a character
SEE ALSO
mklocale(1), setlocale(3), stdio(3), big5(5), euc(5), gb18030(5),
gb2312(5), gbk(5), mskanji(5), utf8(5)
STANDARDS
These functions conform to ISO/IEC 9899:1999 (``ISO C99'').
BSD April 8, 2004 BSD
Mac OS X 10.8 - Generated Wed Aug 29 14:59:05 CDT 2012