# ICONV

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO

## NAME

| iconv - perform character set conversion

## SYNOPSIS

    #include <iconv.h>

    size_t iconv (iconv_t cd,
                  const char* * inbuf, size_t * inbytesleft,
                  char* * outbuf, size_t * outbytesleft);

## DESCRIPTION

| The argument cd must be a conversion descriptor created using the function iconv_open.

| 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. 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, i.e. *inbytesleft has gone down to 0. In this case iconv returns the number of non-reversible 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.

## RETURN VALUE

| The iconv function returns the number of characters converted in a non-reversible way during this call; reversible conversions are not counted. In case of error, it sets errno and returns (size_t)(-1).

## ERRORS

| 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.

## CONFORMING TO

| POSIX:2001

## SEE ALSO

| iconv_open(3), iconvctl(3) iconv_close(3)