iconv_open — allocate descriptor for character set conversion


#include <iconv.h>
iconv_t iconv_open( const char *tocode,
  const char *fromcode);


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 GNU C library, the permitted values are listed by the iconv −−list command, and all combinations of the listed values are supported. Furthermore the GNU C library and the GNU libiconv library support the following two suffixes:


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 similarly looking characters.


When the string "//IGNORE" 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(3) any number of times. It remains valid until deallocated using iconv_close(3).

A conversion descriptor contains a conversion state. After creation using iconv_open(), the state is in the initial state. Using iconv(3) 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(3) with NULL as inbuf argument.


The iconv_open() function returns a freshly allocated conversion descriptor. In case of error, it sets errno and returns (iconv_t) −1.


The following error can occur, among others:


The conversion from fromcode to tocode is not supported by the implementation.


This function is available in glibc since version 2.1.


UNIX98, POSIX.1-2001.


iconv(1), iconv(3), iconv_close(3)


This page is part of release 3.52 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at−pages/.

  Copyright (c) Bruno Haible <>

This is free documentation; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.

References consulted:
  GNU glibc-2 source code and manual
  OpenGroup's Single UNIX specification

2007-03-31 Bruno Haible, Describe the glibc/libiconv //TRANSLIT
and //IGNORE extensions for 'tocode'.