символьная строка (перезапускаемая) (character string (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)
mbsnrtowcs, mbsrtowcs — convert a character string to a wide-
character string (restartable)
Синопсис (Synopsis)
#include <wchar.h>
size_t mbsnrtowcs(wchar_t *restrict dst, const char **restrict src,
size_t nmc, size_t len, mbstate_t *restrict ps);
size_t mbsrtowcs(wchar_t *restrict dst, const char **restrict src,
size_t len, mbstate_t *restrict ps);
Описание (Description)
For mbsrtowcs(): 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.
The mbsrtowcs() function shall convert a sequence of characters,
beginning in the conversion state described by the object pointed
to by ps, from the array indirectly pointed to by src into a
sequence of corresponding wide characters. If dst is not a null
pointer, the converted characters shall be stored into the array
pointed to by dst. Conversion continues up to and including a
terminating null character, which shall also be stored.
Conversion shall stop early in either of the following cases:
* A sequence of bytes is encountered that does not form a valid
character.
* len codes have been stored into the array pointed to by dst
(and dst is not a null pointer).
Each conversion shall take place as if by a call to the mbrtowc()
function.
If dst is not a null pointer, the pointer object pointed to by
src shall be assigned either a null pointer (if conversion
stopped due to reaching a terminating null character) or the
address just past the last character converted (if any). If
conversion stopped due to reaching a terminating null character,
and if dst is not a null pointer, the resulting state described
shall be the initial conversion state.
If ps is a null pointer, the mbsrtowcs() 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 mbsnrtowcs() function shall be equivalent to the mbsrtowcs()
function, except that the conversion of characters indirectly
pointed to by src is limited to at most nmc bytes (the size of
the input buffer), and under conditions where mbsrtowcs() would
assign the address just past the last character converted (if
any) to the pointer object pointed to by src, mbsnrtowcs() shall
instead assign the address just past the last byte processed (if
any) to that pointer object. 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. In the latter case, a subsequent call to
mbsnrtowcs() with an input buffer that starts with the remainder
of the incomplete character shall correctly complete the
conversion of that character.
The behavior of these functions shall be affected by the LC_CTYPE
category of the current locale.
The implementation shall behave as if no function defined in this
volume of POSIX.1‐2017 calls these functions.
The mbsnrtowcs() and mbsrtowcs() functions need not be thread-
safe if called with a NULL ps argument.
The mbsrtowcs() function shall not change the setting of errno if
successful.
Возвращаемое значение (Return value)
If the input conversion encounters a sequence of bytes that do
not form a valid character, an encoding error occurs. In this
case, these functions shall store the value of the macro [EILSEQ]
in errno and shall return (size_t)-1; the conversion state is
undefined. Otherwise, these functions shall return the number of
characters successfully converted, not including the terminating
null (if any).
Ошибки (Error)
These functions 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.
These functions 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)
A future version may require that when the input buffer ends with
an incomplete character, conversion stops at the end of the input
buffer.
Смотри также (See also)
iconv(3p), mbrtowc(3p), mbsinit(3p)
The Base Definitions volume of POSIX.1‐2017, wchar.h(0p)
