MBCHAR(3C-SVR4)     RISC/os Reference Manual      MBCHAR(3C-SVR4)



NAME
     mbchar: mbtowc, mblen, wctomb - multibyte character handling

SYNOPSIS
     #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
     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 stdlib.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 mul-
     tibyte 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 exam-
     ined, 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.




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MBCHAR(3C-SVR4)     RISC/os Reference Manual      MBCHAR(3C-SVR4)



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

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

     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; other-
     wise it returns the number of bytes that comprise the multi-
     byte character corresponding to the value of wchar.

SEE ALSO
     mbstring(3C), setlocale(3C), environ(5).
     chrtbl(1M) in the System Administrator's Reference Manual.



































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