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);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       mbsnrtowcs():
           Since glibc 2.10:
               _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _GNU_SOURCE

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 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 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, excluding 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 memory, and that no destination length limit exists.

       In  both  of  the  above  cases,  if  ps  is  a  NULL pointer, a static anonymous state known only 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

       POSIX.1-2008.

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 3.54 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                                                2011-10-01                                      MBSNRTOWCS(3)