MBRTOWC(3)		   Linux Programmers Manual		   MBRTOWC(3)



NAME
       mbrtowc - convert a multibyte sequence to a wide character

SYNOPSIS
       #include 

       size_t mbrtowc(wchar_t *pwc, const char *s, size_t n, mbstate_t *ps);

DESCRIPTION
       The  main  case	for this function is when s is not NULL and pwc is not
       NULL.  In this case, the mbrtowc() function inspects at most n bytes of
       the  multibyte  string starting at s, extracts the next complete multi
       byte character, converts it to a wide character and stores it at  *pwc.
       It updates the shift state *ps.	If the converted wide character is not
       L'\0', it returns the number of bytes that were consumed  from  s.   If
       the converted wide character is L'\0', it resets the shift state *ps to
       the initial state and returns 0.

       If the n bytes starting at s do not contain a complete multibyte  char
       acter,  mbrtowc()  returns  (size_t) -2.   This can happen even if n >=
       MB_CUR_MAX, if the multibyte string contains redundant shift sequences.

       If  the	multibyte  string  starting at s contains an invalid multibyte
       sequence  before  the  next  complete  character,   mbrtowc()   returns
       (size_t) -1 and sets errno to EILSEQ.  In this case, the effects on *ps
       are undefined.

       A different case is when s is not NULL but pwc is NULL.	In  this  case
       the  mbrtowc() function behaves as above, except that it does not store
       the converted wide character in memory.

       A third case is when s is NULL.	In this case, pwc and n  are  ignored.
       If the conversion state represented by *ps denotes an incomplete multi
       byte character conversion, the mbrtowc() function returns  (size_t) -1,
       sets errno to EILSEQ, and leaves *ps in an undefined state.  Otherwise,
       the mbrtowc() function puts *ps in the initial state and returns 0.

       In all of the above cases, if ps is a NULL pointer, a static  anonymous
       state  only  known to the mbrtowc function is used instead.  Otherwise,
       *ps must be a valid mbstate_t object.  An mbstate_t  object  a  can  be
       initialized to the initial state by zeroing it, for example using

	   memset(&a, 0, sizeof(a));

RETURN VALUE
       The  mbrtowc()  function  returns  the  number of bytes parsed from the
       multibyte sequence starting at s, if a  non-L'\0'  wide	character  was
       recognized.   It  returns  0, if a L'\0' wide character was recognized.
       It returns (size_t) -1 and sets errno to EILSEQ, if an  invalid	multi
       byte  sequence  was encountered.  It returns (size_t) -2 if it couldnt
       parse  a  complete  multibyte  character,  meaning  that  n  should  be
       increased.

CONFORMING TO
       C99.

NOTES
       The  behavior of mbrtowc() depends on the LC_CTYPE category of the cur
       rent locale.

SEE ALSO
       mbsrtowcs(3)

COLOPHON
       This page is part of release 3.05 of the Linux  man-pages  project.   A
       description  of	the project, and information about reporting bugs, can
       be found at http://www.kernel.org/doc/man-pages/.



GNU				  2001-11-22			    MBRTOWC(3)