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 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  point‐
          ing  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 charac‐
          ters 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 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.

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), mbrtowc(3), mbsinit(3), mbsnrtowcs(3), mbstowcs(3)

COLOPHON
       This page is part of release 3.74 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 http://www.kernel.org/doc/man-pages/.



GNU                                         2014-03-18                               MBSRTOWCS(3)