mbsnrtowcs(3) - Linux manual page (original) (raw)

mbsnrtowcs(3) Library Functions Manual mbsnrtowcs(3)

NAME top

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

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <wchar.h>**

   **size_t mbsnrtowcs(wchar_t** _dest_**[restrict .**_size_**], const char restrict** _src_**,**
                     **size_t** _nms_**, size_t** _size_**, mbstate_t *restrict** _ps_**);**

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

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

DESCRIPTION top

   The **mbsnrtowcs**() function is like the [mbsrtowcs(3)](../man3/mbsrtowcs.3.html) 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 _size_ 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:

   •  An invalid multibyte sequence has been encountered.  In this
      case, _*src_ is left pointing to the invalid multibyte sequence,
      _(sizet) -1_ is returned, and _[errno](../man3/errno.3.html)_ is set to **EILSEQ**.

   •  The _nms_ limit forces a stop, or _size_ 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.

   •  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, _size_ is ignored, and the conversion proceeds as
   above, except that the converted wide characters are not written
   out to memory, and that no destination size 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 _size_
   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, _(sizet) -1_ is returned, and
   _[errno](../man3/errno.3.html)_ set to **EILSEQ**.

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────┬───────────────┬─────────────────────────────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────┼───────────────┼─────────────────────────────────┤
   │ **mbsnrtowcs**() │ Thread safety │ MT-Unsafe race:mbsnrtowcs/!ps   │
   └──────────────┴───────────────┴─────────────────────────────────┘

STANDARDS top

   POSIX.1-2008.

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)](../man3/iconv.3.html), [mbrtowc(3)](../man3/mbrtowc.3.html), [mbsinit(3)](../man3/mbsinit.3.html), [mbsrtowcs(3)](../man3/mbsrtowcs.3.html)

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Linux man-pages 6.10 2024-11-17 mbsnrtowcs(3)

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