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   mbrlen.3p    ( 3 )

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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.

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Имя (Name)

mbrlen — get number of bytes in a character (restartable)

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Синопсис (Synopsis)

#include <wchar.h>

       size_t mbrlen(const char *restrict s, size_t n,
           mbstate_t *restrict ps);

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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.

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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.

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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.

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Примеры (Examples)

None.

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Использование в приложениях (Application usage)

None.

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Обоснование (Rationale)

None.

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Будущие направления (Future directions)

None.

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Смотри также (See also)

mbsinit(3p), mbrtowc(3p)

       The Base Definitions volume of POSIX.1‐2017, wchar.h(0p)

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