NAME

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

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <wchar.h>

       size_t wcsnrtombs(char dest[restrict .len], const wchar_t **restrict src,
                         size_t nwc, size_t len, mbstate_t *restrict ps);

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

       wcsnrtombs():
           Since glibc 2.10:
               _POSIX_C_SOURCE >= 200809L
           Before glibc 2.10:
               _GNU_SOURCE

DESCRIPTION

       The  wcsnrtombs()  function  is  like the wcsrtombs(3) function, except that the number of
       wide characters to be converted, starting at *src, is limited to nwc.

       If dest is not NULL, the wcsnrtombs() function converts at most nwc wide  characters  from
       the  wide-character string *src to a multibyte string starting at dest.  At most len bytes
       are written to dest.  The shift state *ps  is  updated.   The  conversion  is  effectively
       performed  by  repeatedly  calling wcrtomb(dest, *src, ps), as long as this call succeeds,
       and then incrementing dest by the number of bytes written and *src by one.  The conversion
       can stop for three reasons:

       •  A  wide  character  has  been  encountered  that  can not be represented as a multibyte
          sequence (according to the current locale).  In this case, *src is left pointing to the
          invalid wide character, (size_t) -1 is returned, and errno is set to EILSEQ.

       •  nwc  wide  characters  have  been  converted without encountering a null wide character
          (L'\0'), or the length limit forces a stop.  In this case, *src is left pointing to the
          next  wide  character  to  be  converted,  and  the  number of bytes written to dest is
          returned.

       •  The wide-character string has been completely converted, including the terminating null
          wide  character  (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 bytes written to  dest,  excluding
          the terminating null byte ('\0'), is returned.

       If  dest  is  NULL,  len is ignored, and the conversion proceeds as above, except that the
       converted bytes 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
       wcsnrtombs() function is used instead.

       The programmer must ensure that there is room for at least len bytes at dest.

RETURN VALUE

       The wcsnrtombs() function returns the number of bytes that make up the converted  part  of
       multibyte  sequence,  not  including  the  terminating null byte.  If a wide character was
       encountered which could not be converted,  (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                                                     │
       ├─────────────┼───────────────┼───────────────────────────────────────────────────────────┤
       │wcsnrtombs() │ Thread safety │ MT-Unsafe race:wcsnrtombs/!ps                             │
       └─────────────┴───────────────┴───────────────────────────────────────────────────────────┘

STANDARDS

       POSIX.1-2008.

NOTES

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

       Passing NULL as ps is not multithread safe.

SEE ALSO

       iconv(3), mbsinit(3), wcsrtombs(3)