получить количество байтов в символе (перезапускается) (get number of bytes in a character (restartable))
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
mbrlen — get number of bytes in a character (restartable)
Синопсис (Synopsis)
#include <wchar.h>
size_t mbrlen(const char *restrict s, size_t n,
mbstate_t *restrict ps);
Описание (Description)
The functionality described on this reference page is aligned
with the ISO C standard. Any conflict between the requirements
described here and the ISO C standard is unintentional. This
volume of POSIX.1‐2017 defers to the ISO C standard.
If s is not a null pointer, mbrlen() shall determine the number
of bytes constituting the character pointed to by s. It shall be
equivalent to:
mbstate_t internal;
mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);
If ps is a null pointer, the mbrlen() function shall use its own
internal mbstate_t object, which is initialized at program start-
up to the initial conversion state. Otherwise, the mbstate_t
object pointed to by ps shall be used to completely describe the
current conversion state of the associated character sequence.
The implementation shall behave as if no function defined in this
volume of POSIX.1‐2017 calls mbrlen().
The behavior of this function is affected by the LC_CTYPE
category of the current locale.
The mbrlen() function need not be thread-safe if called with a
NULL ps argument.
The mbrlen() function shall not change the setting of errno if
successful.
Возвращаемое значение (Return value)
The mbrlen() function shall return the first of the following
that applies:
0 If the next n or fewer bytes complete the character
that corresponds to the null wide character.
positive If the next n or fewer bytes complete a valid
character; the value returned shall be the number of
bytes that complete the character.
(size_t)-2 If the next n bytes contribute to an incomplete but
potentially valid character, and all n bytes have
been processed. When n has at least the value of the
{MB_CUR_MAX} macro, this case can only occur if s
points at a sequence of redundant shift sequences
(for implementations with state-dependent encodings).
(size_t)-1 If an encoding error occurs, in which case the next n
or fewer bytes do not contribute to a complete and
valid character. In this case, [EILSEQ] shall be
stored in errno and the conversion state is
undefined.
Ошибки (Error)
The mbrlen() function shall fail if:
EILSEQ An invalid character sequence is detected. In the POSIX
locale an [EILSEQ] error cannot occur since all byte
values are valid characters.
The mbrlen() function may fail if:
EINVAL ps points to an object that contains an invalid conversion
state.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
mbsinit(3p), mbrtowc(3p)
The Base Definitions volume of POSIX.1‐2017, wchar.h(0p)
