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



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

SYNOPSIS
       #define _GNU_SOURCE
       #include <wchar.h>

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

DESCRIPTION
       The mbsnrtowcs() function is like the mbsrtowcs(3) function, except that the number of bytes to be converted, starting at
       *src, is limited to nms.

       If dest is not a NULL pointer, the mbsnrtowcs() function converts at most nms bytes from 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 mbrtowc(dest, *src, n, ps) where n is some  posi-
       tive  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. The  nms  limit  forces  a stop, or 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 '\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, excluding the terminating L'\0' 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 memory, and that no destination length limit exists.

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

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

RETURN VALUE
       The  mbsnrtowcs()  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.

CONFORMING TO
       This function is a GNU extension.

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

       Passing NULL as ps is not multithread safe.

SEE ALSO
       iconv(3), mbsrtowcs(3)

COLOPHON
       This  page  is  part of release 3.25 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                                                        2007-07-26                                              MBSNRTOWCS(3)