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