MBRTOWC(3)		   Linux Programmer's Manual		    MBRTOWC(3)



NAME
       mbrtowc - convert a multibyte sequence to a wide character

SYNOPSIS
       #include <wchar.h>

       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' (the null wide character), 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 NULL, a static anonymous state
       known only to the mbrtowc() function is used instead.   Otherwise,  *ps
       must  be	 a  valid mbstate_t object.  An mbstate_t object a can be ini-
       tialized 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  couldn't
       parse  a	 complete  multibyte  character,  meaning  that	 n  should  be
       increased.

ATTRIBUTES
       For  an	explanation  of	 the  terms  used   in	 this	section,   see
       attributes(7).

       +----------+---------------+----------------------------+
       |Interface | Attribute	  | Value		       |
       +----------+---------------+----------------------------+
       |mbrtowc() | Thread safety | MT-Unsafe race:mbrtowc/!ps |
       +----------+---------------+----------------------------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, C99.

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

SEE ALSO
       mbsinit(3), mbsrtowcs(3)

COLOPHON
       This page is part of release 4.10 of the Linux  man-pages  project.   A
       description  of	the project, information about reporting bugs, and the
       latest	 version    of	  this	  page,	   can	   be	  found	    at
       https://www.kernel.org/doc/man-pages/.



GNU				  2015-08-08			    MBRTOWC(3)