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  a NULL pointer, 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  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. 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 length limit exists.

       In  both  of  the  above  cases,  if  ps  is  a  NULL pointer, 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.

CONFORMING TO

       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), mbsnrtowcs(3), mbstowcs(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                                                2011-09-28                                       MBSRTOWCS(3)