iconv_open(3) Library Functions Manual iconv_open(3)
NAME
iconv_open - allocate descriptor for character set conversion
SYNOPSIS
#include <iconv.h>
iconv_t iconv_open (const char* tocode, const char* fromcode);
DESCRIPTION
The iconv_open function allocates a conversion descriptor suitable for
converting byte sequences from character encoding fromcode to character
encoding tocode.
The values permitted for fromcode and tocode and the supported
combinations are system dependent. For the libiconv library, the
following encodings are supported, in all combinations.
European languages
ASCII, ISO-8859-{1,2,3,4,5,7,9,10,13,14,15,16}, KOI8-R, KOI8-U,
KOI8-RU, CP{1250,1251,1252,1253,1254,1257}, CP{850,866,1131},
Mac{Roman,CentralEurope,Iceland,Croatian,Romania},
Mac{Cyrillic,Ukraine,Greek,Turkish}, Macintosh
Semitic languages
ISO-8859-{6,8}, CP{1255,1256}, CP862, Mac{Hebrew,Arabic}
Japanese
EUC-JP, SHIFT_JIS, CP932, ISO-2022-JP, ISO-2022-JP-2,
ISO-2022-JP-1, ISO-2022-JP-MS
Chinese
EUC-CN, HZ, GBK, CP936, GB18030, GB18030:2022, EUC-TW, BIG5,
CP950, BIG5-HKSCS, BIG5-HKSCS:2004, BIG5-HKSCS:2001,
BIG5-HKSCS:1999, ISO-2022-CN, ISO-2022-CN-EXT
Korean
EUC-KR, CP949, ISO-2022-KR, JOHAB
Armenian
ARMSCII-8
Georgian
Georgian-Academy, Georgian-PS
Tajik
KOI8-T
Kazakh
PT154, RK1048
Thai
TIS-620, CP874, MacThai
Laotian
MuleLao-1, CP1133
Vietnamese
VISCII, TCVN, CP1258
Platform specifics
HP-ROMAN8, NEXTSTEP
Full Unicode
UTF-8
UCS-2, UCS-2BE, UCS-2LE
UCS-4, UCS-4BE, UCS-4LE
UTF-16, UTF-16BE, UTF-16LE
UTF-32, UTF-32BE, UTF-32LE
UTF-7
C99, JAVA
Full Unicode, in terms of uint16_t or uint32_t
(with machine dependent endianness and alignment)
UCS-2-INTERNAL, UCS-4-INTERNAL
Locale dependent, in terms of char or wchar_t
(with machine dependent endianness and alignment, and with
semantics depending on the OS and the current LC_CTYPE locale
facet)
char, wchar_t
When configured with the option --enable-extra-encodings, it also
provides support for a few extra encodings:
European languages
CP{437,737,775,852,853,855,857,858,860,861,863,865,869,1125}
Semitic languages
CP864
Japanese
EUC-JISX0213, Shift_JISX0213, ISO-2022-JP-3
Chinese
BIG5-2003 (experimental)
Turkmen
TDS565
Platform specifics
ATARIST, RISCOS-LATIN1
EBCDIC compatible (not ASCII compatible, very rarely used)
European languages:
IBM-{037,273,277,278,280,282,284,285,297,423,500,870,871,875,880},
IBM-{905,924,1025,1026,1047,1112,1122,1123,1140,1141,1142,1143},
IBM-{1144,1145,1146,1147,1148,1149,1153,1154,1155,1156,1157,1158},
IBM-{1165,1166,4971}
Semitic languages:
IBM-{424,425,12712,16804}
Persian:
IBM-1097
Thai:
IBM-{838,1160}
Laotian:
IBM-1132
Vietnamese:
IBM-{1130,1164}
Indic languages:
IBM-1137
The empty encoding name "" is equivalent to "char": it denotes the
locale dependent character encoding.
When the string "//TRANSLIT" is appended to tocode, transliteration is
activated. This means that when a character cannot be represented in
the target character set, it can be approximated through one or several
characters that look similar to the original character.
When the string "//IGNORE" is appended to tocode, invalid multibyte
sequences in the input and characters that cannot be represented in the
target character set will be silently discarded.
When the string "//NON_IDENTICAL_DISCARD" is appended to tocode,
characters that cannot be represented in the target character set will
be silently discarded.
The resulting conversion descriptor can be used with iconv any number
of times. It remains valid until deallocated using iconv_close.
A conversion descriptor contains a conversion state. After creation
using iconv_open, the state is in the initial state. Using iconv
modifies the descriptor's conversion state. (This implies that a
conversion descriptor can not be used in multiple threads
simultaneously.) To bring the state back to the initial state, use
iconv with NULL as inbuf argument.
RETURN VALUE
The iconv_open function returns a freshly allocated conversion
descriptor. In case of error, it sets errno and returns (iconv_t)(-1).
ERRORS
The following error can occur, among others:
EINVAL The conversion from fromcode to tocode is not supported by the
implementation.
CONFORMING TO
POSIX:2024
SEE ALSO
iconv(3) iconvctl(3) iconv_close(3)
GNU December 15, 2024 iconv_open(3)
libiconv 1.18 - Generated Thu Mar 5 15:14:13 CST 2026