выполнить преобразование набора символов (perform character set conversion)
Имя (Name)
iconv - perform character set conversion
Синопсис (Synopsis)
#include <iconv.h>
size_t iconv(iconv_t
cd,
char **restrict
inbuf, size_t *restrict
inbytesleft,
char **restrict
outbuf, size_t *restrict
outbytesleft);
Описание (Description)
The iconv
() function converts a sequence of characters in one
character encoding to a sequence of characters in another
character encoding. The cd argument is a conversion descriptor,
previously created by a call to iconv_open(3); the conversion
descriptor defines the character encodings that iconv
() uses for
the conversion. The inbuf argument is the address of a variable
that points to the first character of the input sequence;
inbytesleft indicates the number of bytes in that buffer. The
outbuf argument is the address of a variable that points to the
first byte available in the output buffer; outbytesleft indicates
the number of bytes available in the output buffer.
The main case is when inbuf is not NULL and *inbuf is not NULL.
In this case, the iconv
() function converts the multibyte
sequence starting at *inbuf to a multibyte sequence starting at
*outbuf. At most *inbytesleft bytes, starting at *inbuf, will be
read. At most *outbytesleft bytes, starting at *outbuf, will be
written.
The iconv
() function converts one multibyte character at a time,
and for each character conversion it increments *inbuf and
decrements *inbytesleft by the number of converted input bytes,
it increments *outbuf and decrements *outbytesleft by the number
of converted output bytes, and it updates the conversion state
contained in cd. If the character encoding of the input is
stateful, the iconv
() function can also convert a sequence of
input bytes to an update to the conversion state without
producing any output bytes; such input is called a shift
sequence. The conversion can stop for four reasons:
1. An invalid multibyte sequence is encountered in the input. In
this case, it sets errno to EILSEQ
and returns (size_t) -1.
*inbuf is left pointing to the beginning of the invalid
multibyte sequence.
2. The input byte sequence has been entirely converted, that is,
*inbytesleft has gone down to 0. In this case, iconv
()
returns the number of nonreversible conversions performed
during this call.
3. An incomplete multibyte sequence is encountered in the input,
and the input byte sequence terminates after it. In this
case, it sets errno to EINVAL
and returns (size_t) -1. *inbuf
is left pointing to the beginning of the incomplete multibyte
sequence.
4. The output buffer has no more room for the next converted
character. In this case, it sets errno to E2BIG
and returns
(size_t) -1.
A different case is when inbuf is NULL or *inbuf is NULL, but
outbuf is not NULL and *outbuf is not NULL. In this case, the
iconv
() function attempts to set cd's conversion state to the
initial state and store a corresponding shift sequence at
*outbuf. At most *outbytesleft bytes, starting at *outbuf, will
be written. If the output buffer has no more room for this reset
sequence, it sets errno to E2BIG
and returns (size_t) -1.
Otherwise, it increments *outbuf and decrements *outbytesleft by
the number of bytes written.
A third case is when inbuf is NULL or *inbuf is NULL, and outbuf
is NULL or *outbuf is NULL. In this case, the iconv
() function
sets cd's conversion state to the initial state.
Возвращаемое значение (Return value)
The iconv
() function returns the number of characters converted
in a nonreversible way during this call; reversible conversions
are not counted. In case of error, iconv
() returns (size_t) -1
and sets errno to indicate the error.
Ошибки (Error)
The following errors can occur, among others:
E2BIG
There is not sufficient room at *outbuf.
EILSEQ
An invalid multibyte sequence has been encountered in the
input.
EINVAL
An incomplete multibyte sequence has been encountered in
the input.
Версии (Versions)
This function is available in glibc since version 2.1.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────┬───────────────┬─────────────────┐
│Interface
│ Attribute
│ Value
│
├──────────────────────────────┼───────────────┼─────────────────┤
│iconv
() │ Thread safety │ MT-Safe race:cd │
└──────────────────────────────┴───────────────┴─────────────────┘
The iconv
() function is MT-Safe, as long as callers arrange for
mutual exclusion on the cd argument.
Стандарты (Conforming to)
POSIX.1-2001, POSIX.1-2008.
Примечание (Note)
In each series of calls to iconv
(), the last should be one with
inbuf or *inbuf equal to NULL, in order to flush out any
partially converted input.
Although inbuf and outbuf are typed as char **, this does not
mean that the objects they point can be interpreted as C strings
or as arrays of characters: the interpretation of character byte
sequences is handled internally by the conversion functions. In
some encodings, a zero byte may be a valid part of a multibyte
character.
The caller of iconv
() must ensure that the pointers passed to the
function are suitable for accessing characters in the appropriate
character set. This includes ensuring correct alignment on
platforms that have tight restrictions on alignment.
Смотри также (See also)
iconv_close(3), iconv_open(3), iconvconfig(8)