Originální popis anglicky:
mbrtowc - convert a character to a wide-character code (restartable)
Návod, kniha: POSIX Programmer's Manual
#include <wchar.h>
size_t mbrtowc(wchar_t *restrict
pwc, const char
*restrict s,
size_t
n, mbstate_t *restrict
ps);
If
s is a null pointer, the
mbrtowc() function shall be equivalent
to the call:
In this case, the values of the arguments
pwc and
n are ignored.
If
s is not a null pointer, the
mbrtowc() function shall inspect
at most
n bytes beginning at the byte pointed to by
s to
determine the number of bytes needed to complete the next character (including
any shift sequences). If the function determines that the next character is
completed, it shall determine the value of the corresponding wide character
and then, if
pwc is not a null pointer, shall store that value in the
object pointed to by
pwc. If the corresponding wide character is the
null wide character, the resulting state described shall be the initial
conversion state.
If
ps is a null pointer, the
mbrtowc() function shall use its own
internal
mbstate_t object, which shall be 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
IEEE Std 1003.1-2001 calls
mbrtowc().
The behavior of this function is affected by the
LC_CTYPE category of the
current locale.
The
mbrtowc() 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 (which is the value
stored).
- between 1 and n inclusive
-
If the next n or fewer bytes complete a valid character (which is the
value stored); 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
(no value is stored). 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 (no value is stored). In this case, [EILSEQ] shall be stored in
errno and the conversion state is undefined.
The
mbrtowc() function may fail if:
- EINVAL
- ps points to an object that contains an invalid
conversion state.
- EILSEQ
- Invalid character sequence is detected.
The following sections are informative.
None.
None.
None.
None.
mbsinit() , the Base Definitions volume of
IEEE Std 1003.1-2001,
<wchar.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
