Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

Linux 2.6 - man page for iconv (linux section 3)

ICONV(3)						     Linux Programmer's Manual							  ICONV(3)

NAME
iconv - perform character set conversion
SYNOPSIS
#include <iconv.h> size_t iconv(iconv_t cd, 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(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 start- ing at *inbuf to a multibyte sequence starting at *outbuf. At most *inbytesleft bytes, starting at *inbuf, will be read. At most *out- bytesleft 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() func- tion 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.
CAVEAT
The type of inbuf and outbuf, char **, does not imply that the objects pointed to are interpreted as null-terminated C strings or arrays of characters. The caller of iconv has to make sure that the pointers passed to the function are suitable for access of characters from the appropriate character set. This includes alignment on platforms that have tight restriction on alignment.
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, 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.
VERSIONS
This function is available in glibc since version 2.1.
CONFORMING TO
POSIX.1-2001.
SEE ALSO
iconv_close(3), iconv_open(3)
COLOPHON
This page is part of release 3.27 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)