mbsrtowcs

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 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 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.

ATTRIBUTES
       For an explanation of the terms used in this section, see attributes(7).

       ┌────────────┬───────────────┬──────────────────────────────┐
       │Interface   Attribute     Value                        │
       ├────────────┼───────────────┼──────────────────────────────┤
       │mbsrtowcs() │ Thread safety │ MT-Unsafe race:mbsrtowcs/!ps │
       └────────────┴───────────────┴──────────────────────────────┘

CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, 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 5.09 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
       https://www.kernel.org/doc/man-pages/.



GNU                                2019-03-06                       MBSRTOWCS(3)