преобразовать многобайтовую строку в строку расширенных символов (convert a multibyte string to a wide-character string)
Имя (Name)
mbsnrtowcs - convert a multibyte string to a wide-character
string
Синопсис (Synopsis)
#include <wchar.h>
size_t mbsnrtowcs(wchar_t *restrict dest, const char **restrict src,
size_t nms, size_t len, 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
Описание (Description)
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.
Возвращаемое значение (Return value)
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.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌─────────────┬───────────────┬──────────────────────────────────┐
│Interface │ Attribute │ Value │
├─────────────┼───────────────┼──────────────────────────────────┤
│mbsnrtowcs() │ Thread safety │ MT-Unsafe race:mbsnrtowcs/!ps │
└─────────────┴───────────────┴──────────────────────────────────┘
Стандарты (Conforming to)
POSIX.1-2008.
Примечание (Note)
The behavior of mbsnrtowcs() depends on the LC_CTYPE category of
the current locale.
Passing NULL as ps is not multithread safe.
Смотри также (See also)
iconv(3), mbrtowc(3), mbsinit(3), mbsrtowcs(3)
