mbchar(3C)							    mbchar(3C)

NAME    [Toc]    [Back]

     mbchar: mbtowc, mblen, wctomb - multibyte character handling

SYNOPSIS    [Toc]    [Back]

     #include <stdlib.h>

     int mbtowc	(wchar_t *pwc, const char *s, size_t n);

     int mblen (const char *s, size_t n);

     int wctomb	(char *s, wchar_t wchar);

DESCRIPTION    [Toc]    [Back]

     Multibyte characters are used to represent	characters in an extended
     character set.  This is needed for	locales	where 8	bits are not enough to
     represent all the characters in the character set.

     The multibyte character handling functions	provide	the means of
     translating multibyte characters into wide	characters and back again.
     Wide characters have type wchar_t (defined	in stdlib.h), which is an
     integral type whose range of values can represent distinct	codes for all
     members of	the largest extended character set specified among the
     supported locales.

     A maximum of 3 extended character sets are	supported for each locale.
     The number	of bytes in an extended	character set is defined by the
     LC_CTYPE category of the locale [see setlocale(3C)].  However, the
     maximum number of bytes in	any multibyte character	will never be greater
     than MB_LEN_MAX.  which is	defined	in limits.h.  The maximum number of
     bytes in a	character in an	extended character set in the current locale
     is	given by the macro, MB_CUR_MAX,	also defined in	stdlib.h.

     mbtowc determines the number of bytes that	comprise the multibyte
     character pointed to by s.	 Also, if pwc is not a null pointer, mbtowc
     converts the multibyte character to a wide	character and places the
     result in the object pointed to by	pwc. (The value	of the wide character
     corresponding to the null character is zero.)  At most n characters will
     be	examined, starting at the character pointed to by s.

     If	s is a null pointer, mbtowc simply returns 0.  If s is not a null
     pointer, then, if s points	to the null character, mbtowc returns 0; if
     the next n	or fewer bytes form a valid multibyte character, mbtowc
     returns the number	of bytes that comprise the converted multibyte
     character;	otherwise, s does not point to a valid multibyte character and
     mbtowc returns -1.

     mblen determines the number of bytes comprising the multibyte character
     pointed to	by s.  It is equivalent	to

	  mbtowc ((wchar_t *)0,	s, n);





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mbchar(3C)							    mbchar(3C)



     wctomb determines the number of bytes needed to represent the multibyte
     character corresponding to	the code whose value is	wchar, and, if s is
     not a null	pointer, stores	the multibyte character	representation in the
     array pointed to by s.  At	most MB_CUR_MAX	characters are stored.

     If	s is a null pointer, wctomb simply returns 0.  If s is not a null
     pointer, wctomb returns -1	if the value of	wchar does not correspond to a
     valid multibyte character;	otherwise it returns the number	of bytes that
     comprise the multibyte character corresponding to the value of wchar.

SEE ALSO    [Toc]    [Back]

     wchrtbl(1M), mbstring(3C),	setlocale(3C), environ(5).


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