IDN2_DOMAIN_MAX_LENGTH

#define IDN2_DOMAIN_MAX_LENGTH 255

Constant specifying the maximum size of the wire encoding of a DNS domain to 255 characters, as specified in RFC 1034. Note that the usual printed representation of a domain name is limited to 253 characters if it does not end with a period, or 254 characters if it ends with a period.

IDN2_LABEL_MAX_LENGTH

#define IDN2_LABEL_MAX_LENGTH 63

Constant specifying the maximum length of a DNS label to 63 characters, as specified in RFC 1034.

IDN2_VERSION

#define IDN2_VERSION "0.10"

Pre-processor symbol with a string that describe the header file version number. Used together with idn2_check_version() to verify header file and run-time library consistency.

IDN2_VERSION_NUMBER

#define IDN2_VERSION_NUMBER 0x00090000

Pre-processor symbol with a hexadecimal value describing the header file version number. For example, when the header version is 1.2.4711 this symbol will have the value 0x01021267. The last four digits are used to enumerate development snapshots, but for all public releases they will be 0000.

idn2_check_version ()

const char *        idn2_check_version                  (const char *req_version);

Check IDN2 library version. This function can also be used to read out the version of the library code used. See IDN2_VERSION for a suitable req_version string, it corresponds to the idn2.h header file version. Normally these two version numbers match, but if you are using an application built against an older libidn2 with a newer libidn2 shared library they will be different.

enum idn2_flags

typedef enum {
    IDN2_NFC_INPUT = 1,
    IDN2_ALABEL_ROUNDTRIP = 2,
} idn2_flags;

Flags to IDNA2008 functions, to be binary or:ed together. Specify only 0 if you want the default behaviour.

idn2_free ()

void                idn2_free                           (void *ptr);

Call free(3) on the given pointer.

This function is typically only useful on systems where the library malloc heap is different from the library caller malloc heap, which happens on Windows when the library is a separate DLL.

idn2_lookup_u8 ()

int                 idn2_lookup_u8                      (const uint8_t *src,
                                                         uint8_t **lookupname,
                                                         int flags);

Perform IDNA2008 lookup string conversion on domain name src, as described in section 5 of RFC 5891. Note that the input string must be encoded in UTF-8 and be in Unicode NFC form.

Pass IDN2_NFC_INPUT in flags to convert input to NFC form before further processing. Pass IDN2_ALABEL_ROUNDTRIP in flags to convert any input A-labels to U-labels and perform additional testing. Multiple flags may be specified by binary or:ing them together, for example IDN2_NFC_INPUT | IDN2_ALABEL_ROUNDTRIP.

idn2_lookup_ul ()

int                 idn2_lookup_ul                      (const char *src,
                                                         char **lookupname,
                                                         int flags);

Perform IDNA2008 lookup string conversion on domain name src, as described in section 5 of RFC 5891. Note that the input is assumed to be encoded in the locale's default coding system, and will be transcoded to UTF-8 and NFC normalized by this function.

Pass IDN2_ALABEL_ROUNDTRIP in flags to convert any input A-labels to U-labels and perform additional testing.

enum idn2_rc

typedef enum {
    IDN2_OK = 0,
    IDN2_MALLOC = -100,
    IDN2_NO_CODESET = -101,
    IDN2_ICONV_FAIL = -102,
    IDN2_ENCODING_ERROR = -200,
    IDN2_NFC = -201,
    IDN2_PUNYCODE_BAD_INPUT = -202,
    IDN2_PUNYCODE_BIG_OUTPUT = -203,
    IDN2_PUNYCODE_OVERFLOW = -204,
    IDN2_TOO_BIG_DOMAIN = -205,
    IDN2_TOO_BIG_LABEL = -206,
    IDN2_INVALID_ALABEL = -207,
    IDN2_UALABEL_MISMATCH = -208,
    IDN2_NOT_NFC = -300,
    IDN2_2HYPHEN = -301,
    IDN2_HYPHEN_STARTEND = -302,
    IDN2_LEADING_COMBINING = -303,
    IDN2_DISALLOWED = -304,
    IDN2_CONTEXTJ = -305,
    IDN2_CONTEXTJ_NO_RULE = -306,
    IDN2_CONTEXTO = -307,
    IDN2_CONTEXTO_NO_RULE = -308,
    IDN2_UNASSIGNED = -309,
    IDN2_BIDI = -310
} idn2_rc;

Return codes for IDN2 functions. All return codes are negative except for the successful code IDN2_OK which are guaranteed to be 0. Positive values are reserved for non-error return codes.

Note that the idn2_rc enumeration may be extended at a later date to include new return codes.

idn2_register_u8 ()

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

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.

idn2_register_ul ()

int                 idn2_register_ul                    (const char *ulabel,
                                                         const char *alabel,
                                                         char **insertname,
                                                         int flags);

Perform IDNA2008 register string conversion on domain label ulabel and alabel, as described in section 4 of RFC 5891. Note that the input ulabel is assumed to be encoded in the locale's default coding system, and will be transcoded to UTF-8 and NFC normalized by this function.

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.

idn2_strerror ()

const char *        idn2_strerror                       (int rc);

Convert internal libidn2 error code to a humanly readable string. The returned pointer must not be de-allocated by the caller.

idn2_strerror_name ()

const char *        idn2_strerror_name                  (int rc);

Convert internal libidn2 error code to a string corresponding to internal header file symbols. For example, idn2_strerror_name(IDN2_MALLOC) will return the string "IDN2_MALLOC".

The caller must not attempt to de-allocate the returned string.