mbsnrtowcs(3) — Linux manual page


MBSNRTOWCS(3)             Linux Programmer's Manual            MBSNRTOWCS(3)

NAME         top

       mbsnrtowcs - convert a multibyte string to a wide-character string

SYNOPSIS         top

       #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)):

           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:

DESCRIPTION         top

       The mbsnrtowcs() function is like the mbsrtowcs(3) function, except
       that the number of bytes to be converted, starting at *src, is
       limited to at most nms bytes.

       If dest is not NULL, 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.

       According to POSIX.1, if the input buffer ends with an incomplete
       character, it is unspecified whether conversion stops at the end of
       the previous character (if any), or at the end of the input buffer.
       The glibc implementation adopts the former behavior.

       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 NULL, 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         top

       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.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface    Attribute     Value                         │
       │mbsnrtowcs() │ Thread safety │ MT-Unsafe race:mbsnrtowcs/!ps │

CONFORMING TO         top


NOTES         top

       The behavior of mbsnrtowcs() depends on the LC_CTYPE category of the
       current locale.

       Passing NULL as ps is not multithread safe.

SEE ALSO         top

       iconv(3), mbrtowc(3), mbsinit(3), mbsrtowcs(3)

COLOPHON         top

       This page is part of release 5.08 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

GNU                              2020-06-09                    MBSNRTOWCS(3)

Pages that refer to this page: mbsrtowcs(3)