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.
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 descriptors 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.
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: