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)