idn2_register_u8(3) API function


#include <idn2.h>

int idn2_register_u8(const uint8_t * ulabel, const uint8_t * alabel, uint8_t ** insertname, int flags);


const uint8_t * ulabel
input zero-terminated UTF-8 and Unicode NFC string, or NULL.
const uint8_t * alabel
input zero-terminated ACE encoded string (xn--), or NULL.
uint8_t ** insertname
newly allocated output variable with name to register in DNS.
int flags
optional idn2_flags to modify behaviour.


Perform IDNA2008 register string conversion on domain label ulabel and alabel, as described in section 4 of RFC 5891. Note that the input ulabel must be encoded in UTF-8 and be in Unicode NFC form.

Pass IDN2_NFC_INPUT in flags to convert input ulabel to NFC form before further processing.

It is recommended to supply both ulabel and alabel for better error checking, but supplying just one of them will work. Passing in only alabel is better than only ulabel. See RFC 5891 section 4 for more information.


On successful conversion IDN2_OK is returned, when the given ulabel and alabel does not match each other IDN2_UALABEL_MISMATCH is returned, when either of the input labels are too long IDN2_TOO_BIG_LABEL is returned, when alabel does does not appear to be a proper A-label IDN2_INVALID_ALABEL is returned, or another error code is returned.