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ICONV(3) Linux Programmer's Manual ICONV(3)
iconv - perform character set conversion
#include <iconv.h>
size_t iconv(iconv_t cd,
char **inbuf, size_t *inbytesleft,
char **outbuf, size_t *outbytesleft);
The argument cd must be a conversion descriptor created using the function
iconv_open(3).
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.
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, it sets errno and returns (size_t) -1.
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.
This function is available in glibc since version 2.1.
POSIX.1-2001.
iconv_close(3), iconv_open(3)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2008-09-08 ICONV(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface