NAME

       mbsnrtowcs - convert a multibyte string to a wide character string

SYNOPSIS

       #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 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
       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. 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.

SEE ALSO

       mbsrtowcs(3), iconv(3)

NOTES

       The behaviour of mbsnrtowcs depends on the LC_CTYPE category of the current locale.

       Passing NULL as ps is not multi-thread safe.