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



NAME
       mbsrtowcs - convert a multibyte string to a wide-character string

SYNOPSIS
       #include <wchar.h>

       size_t mbsrtowcs(wchar_t *dest, const char **src,
			 size_t len, mbstate_t *ps);

DESCRIPTION
       If  dest	 is  not NULL, the mbsrtowcs() function converts the multibyte
       string *src to a wide-character string starting at dest.	 At  most  len
       wide  characters	 are written to dest.  The shift state *ps is updated.
       The conversion is effectively  performed	 by  repeatedly	 calling  mbr-
       towc(dest,  *src,  n,  ps)  where n is some positive number, as long as
       this call succeeds, and then incrementing dest by one and *src  by  the
       number of bytes consumed.  The conversion can stop for three reasons:

       1. An  invalid  multibyte sequence has been encountered.	 In this case,
	  *src is left pointing to the invalid multibyte sequence, (size_t) -1
	  is returned, and errno is set to EILSEQ.

       2. len  non-L'\0'  wide	characters  have been stored at dest.  In this
	  case, *src is left pointing to the next  multibyte  sequence	to  be
	  converted,  and  the	number	of  wide characters written to dest is
	  returned.

       3. The multibyte string has been completely  converted,	including  the
	  terminating null wide character ('\0'), which has the side effect of
	  bringing back *ps to the initial state.  In this case, *src  is  set
	  to  NULL, and the number of wide characters written to dest, exclud-
	  ing the terminating null wide character, is returned.

       If dest is NULL, len is ignored, and the conversion proceeds as	above,
       except  that  the converted wide characters are not written out to mem-
       ory, and that no length limit exists.

       In both of the above cases, if ps is NULL,  a  static  anonymous	 state
       known only to the mbsrtowcs() function is used instead.

       The  programmer	must  ensure  that there is room for at least len wide
       characters at dest.

RETURN VALUE
       The mbsrtowcs() function returns the number  of	wide  characters  that
       make  up the converted part of the wide-character string, not including
       the terminating null wide character.  If an invalid multibyte  sequence
       was encountered, (size_t) -1 is returned, and errno set to EILSEQ.

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

       +------------+---------------+------------------------------+
       |Interface   | Attribute	    | Value			   |
       +------------+---------------+------------------------------+
       |mbsrtowcs() | Thread safety | MT-Unsafe race:mbsrtowcs/!ps |
       +------------+---------------+------------------------------+

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, C99.

NOTES
       The behavior of mbsrtowcs() depends on the  LC_CTYPE  category  of  the
       current locale.

       Passing NULL as ps is not multithread safe.

SEE ALSO
       iconv(3), mbrtowc(3), mbsinit(3), mbsnrtowcs(3), mbstowcs(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			  MBSRTOWCS(3)