GCC_VERSION_AT_LEAST()

# define GCC_VERSION_AT_LEAST(major, minor) ((__GNUC__ > (major)) || (__GNUC__ == (major) && __GNUC_MINOR__ >= (minor)))

Pre-processor symbol to check the gcc version.

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. IDN2_TRANSITIONAL and IDN2_NONTRANSITIONAL do already imply IDN2_NFC_INPUT.

Pass IDN2_ALABEL_ROUNDTRIP in flags to convert any input A-labels to U-labels and perform additional testing. This is default since version 2.2. To switch this behavior off, pass IDN2_NO_ALABEL_ROUNDTRIP

Pass IDN2_TRANSITIONAL to enable Unicode TR46 transitional processing, and IDN2_NONTRANSITIONAL to enable Unicode TR46 non-transitional processing.

Multiple flags may be specified by binary or:ing them together.

After version 2.0.3: IDN2_USE_STD3_ASCII_RULES disabled by default. Previously we were eliminating non-STD3 characters from domain strings such as _443._tcp.example.com, or IPs 1.2.3.4/24 provided to libidn2 functions. That was an unexpected regression for applications switching from libidn and thus it is no longer applied by default. Use IDN2_USE_STD3_ASCII_RULES to enable that behavior again.

After version 0.11: lookupname may be NULL to test lookup of src without allocating memory.

Since: 0.1

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.

After version 0.11: insertname may be NULL to test conversion of src without allocating memory.

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. This is default since version 2.2. To switch this behavior off, pass IDN2_NO_ALABEL_ROUNDTRIP

Pass IDN2_TRANSITIONAL to enable Unicode TR46 transitional processing, and IDN2_NONTRANSITIONAL to enable Unicode TR46 non-transitional processing.

Multiple flags may be specified by binary or:ing them together, for example IDN2_ALABEL_ROUNDTRIP | IDN2_NONTRANSITIONAL.

The IDN2_NFC_INPUT in flags is always enabled in this function.

After version 0.11: lookupname may be NULL to test lookup of src without allocating memory.

Since: 0.1

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.

After version 0.11: insertname may be NULL to test conversion of src without allocating memory.

idn2_to_ascii_4i ()

int
idn2_to_ascii_4i (const uint32_t *input,
 size_t inlen,
 char *output,
 int flags);

The ToASCII operation takes a sequence of Unicode code points that make up one domain label and transforms it into a sequence of code points in the ASCII range (0..7F). If ToASCII succeeds, the original sequence and the resulting sequence are equivalent labels.

It is important to note that the ToASCII operation can fail. ToASCII fails if any step of it fails. If any step of the ToASCII operation fails on any label in a domain name, that domain name MUST NOT be used as an internationalized domain name. The method for dealing with this failure is application-specific.

The inputs to ToASCII are a sequence of code points.

ToASCII never alters a sequence of code points that are all in the ASCII range to begin with (although it could fail). Applying the ToASCII operation multiple effect as applying it just once.

The default behavior of this function (when flags are zero) is to apply the IDNA2008 rules without the TR46 amendments. As the TR46 non-transitional processing is nowadays ubiquitous, when unsure, it is recommended to call this function with the IDN2_NONTRANSITIONAL and the IDN2_NFC_INPUT flags for compatibility with other software.

Warning: With version 2.1.1 until before version 2.3.5 this function was deprecated in favor idn2_to_ascii_4i2(). We still encourage you to use idn2_to_ascii_4i2() when appropriate.

Since: 2.0.0

idn2_to_ascii_4i2 ()

int
idn2_to_ascii_4i2 (const uint32_t *input,
 size_t inlen,
 char **output,
 int flags);

The ToASCII operation takes a sequence of Unicode code points that make up one domain label and transforms it into a sequence of code points in the ASCII range (0..7F). If ToASCII succeeds, the original sequence and the resulting sequence are equivalent labels.

It is important to note that the ToASCII operation can fail. ToASCII fails if any step of it fails. If any step of the ToASCII operation fails on any label in a domain name, that domain name MUST NOT be used as an internationalized domain name. The method for dealing with this failure is application-specific.

The inputs to ToASCII are a sequence of code points.

ToASCII never alters a sequence of code points that are all in the ASCII range to begin with (although it could fail). Applying the ToASCII operation multiple effect as applying it just once.

The default behavior of this function (when flags are zero) is to apply the IDNA2008 rules without the TR46 amendments. As the TR46 non-transitional processing is nowadays ubiquitous, when unsure, it is recommended to call this function with the IDN2_NONTRANSITIONAL and the IDN2_NFC_INPUT flags for compatibility with other software.

Since: 2.1.1

idn2_to_ascii_4z ()

int
idn2_to_ascii_4z (const uint32_t *input,
 char **output,
 int flags);

Convert UCS-4 domain name to ASCII string using the IDNA2008 rules. The domain name may contain several labels, separated by dots. The output buffer must be deallocated by the caller.

The default behavior of this function (when flags are zero) is to apply the IDNA2008 rules without the TR46 amendments. As the TR46 non-transitional processing is nowadays ubiquitous, when unsure, it is recommended to call this function with the IDN2_NONTRANSITIONAL and the IDN2_NFC_INPUT flags for compatibility with other software.

Since: 2.0.0

idn2_to_ascii_8z ()

int
idn2_to_ascii_8z (const char *input,
 char **output,
 int flags);

Convert UTF-8 domain name to ASCII string using the IDNA2008 rules. The domain name may contain several labels, separated by dots. The output buffer must be deallocated by the caller.

The default behavior of this function (when flags are zero) is to apply the IDNA2008 rules without the TR46 amendments. As the TR46 non-transitional processing is nowadays ubiquitous, when unsure, it is recommended to call this function with the IDN2_NONTRANSITIONAL and the IDN2_NFC_INPUT flags for compatibility with other software.

Since: 2.0.0

idn2_to_ascii_lz ()

int
idn2_to_ascii_lz (const char *input,
 char **output,
 int flags);

Convert a domain name in locale's encoding to ASCII string using the IDNA2008 rules. The domain name may contain several labels, separated by dots. The output buffer must be deallocated by the caller.

The default behavior of this function (when flags are zero) is to apply the IDNA2008 rules without the TR46 amendments. As the TR46 non-transitional processing is nowadays ubiquitous, when unsure, it is recommended to call this function with the IDN2_NONTRANSITIONAL and the IDN2_NFC_INPUT flags for compatibility with other software.

Since: 2.0.0

idn2_to_unicode_8z4z ()

int
idn2_to_unicode_8z4z (const char *input,
 uint32_t **output,
 int flags);

Converts a possibly ACE encoded domain name in UTF-8 format into a UTF-32 string (punycode decoding). The output buffer will be zero-terminated and must be deallocated by the caller.

output may be NULL to test lookup of input without allocating memory.

Since: 2.0.0

idn2_to_unicode_4z4z ()

int
idn2_to_unicode_4z4z (const uint32_t *input,
 uint32_t **output,
 int flags);

Converts a possibly ACE encoded domain name in UTF-32 format into a UTF-32 string (punycode decoding). The output buffer will be zero-terminated and must be deallocated by the caller.

output may be NULL to test lookup of input without allocating memory.

Since: 2.0.0

idn2_to_unicode_44i ()

int
idn2_to_unicode_44i (const uint32_t *in,
 size_t inlen,
 uint32_t *out,
 size_t *outlen,
 int flags);

The ToUnicode operation takes a sequence of UTF-32 code points that make up one domain label and returns a sequence of UTF-32 code points. If the input sequence is a label in ACE form, then the result is an equivalent internationalized label that is not in ACE form, otherwise the original sequence is returned unaltered.

output may be NULL to test lookup of input without allocating memory.

Since: 2.0.0

idn2_to_unicode_8z8z ()

int
idn2_to_unicode_8z8z (const char *input,
 char **output,
 int flags);

Converts a possibly ACE encoded domain name in UTF-8 format into a UTF-8 string (punycode decoding). The output buffer will be zero-terminated and must be deallocated by the caller.

output may be NULL to test lookup of input without allocating memory.

Since: 2.0.0

idn2_to_unicode_8zlz ()

int
idn2_to_unicode_8zlz (const char *input,
 char **output,
 int flags);

Converts a possibly ACE encoded domain name in UTF-8 format into a string encoded in the current locale's character set (punycode decoding). The output buffer will be zero-terminated and must be deallocated by the caller.

output may be NULL to test lookup of input without allocating memory.

Since: 2.0.0

idn2_to_unicode_lzlz ()

int
idn2_to_unicode_lzlz (const char *input,
 char **output,
 int flags);

Converts a possibly ACE encoded domain name in the locale's character set into a string encoded in the current locale's character set (punycode decoding). The output buffer will be zero-terminated and must be deallocated by the caller.

output may be NULL to test lookup of input without allocating memory.

Since: 2.0.0

idn2_punycode_encode ()

int
idn2_punycode_encode (const uint32_t *input,
 size_t input_length,
 char *output,
 size_t *output_length);

Converts a sequence of code points to Punycode.

Warning: Be aware that is rare for applications to need to perform Punycode operations, and you should consider idn2_to_ascii_8z(), idn2_to_ascii_lz(), idn2_to_ascii_4z() etc.

Since: 2.3.5

idn2_punycode_decode ()

int
idn2_punycode_decode (const char *input,
 size_t input_length,
 uint32_t *output,
 size_t *output_length);

Converts Punycode to a sequence of code points.

The decoder will never need to output more code points than the number of ASCII code points in the input, because of the way the encoding is defined.

The number of code points output cannot exceed the maximum possible value of a uint32_t, even if the supplied output_length is greater than that.

Warning: Be aware that is rare for applications to need to perform Punycode operations, and you should consider idn2_to_unicode_8z8z(), idn2_to_unicode_lzlz() etc.

Since: 2.3.5

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.

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.

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.

G_GNUC_IDN2_ATTRIBUTE_PURE

# define G_GNUC_IDN2_ATTRIBUTE_PURE __attribute__ ((pure))

Function attribute: Function is a pure function.

G_GNUC_IDN2_ATTRIBUTE_CONST

# define G_GNUC_IDN2_ATTRIBUTE_CONST __attribute__ ((const))

Function attribute: Function is a const function.

G_GNUC_UNUSED

# define G_GNUC_UNUSED __attribute__ ((__unused__))

Parameter attribute: Parameter is not used.

IDN2_VERSION

# define IDN2_VERSION "2.3.7"

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 0x02030007

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_VERSION_MAJOR

# define IDN2_VERSION_MAJOR 2

Pre-processor symbol for the major version number (decimal). The version scheme is major.minor.patchlevel.

IDN2_VERSION_MINOR

# define IDN2_VERSION_MINOR 3

Pre-processor symbol for the minor version number (decimal). The version scheme is major.minor.patchlevel.

IDN2_VERSION_PATCH

# define IDN2_VERSION_PATCH 7

Pre-processor symbol for the patch level number (decimal). The version scheme is major.minor.patchlevel.

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_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.

enum idn2_flags

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

enum idn2_rc

Return codes for IDN2 functions. All return codes are negative except for the successful code IDN2_OK which are guaranteed to be

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