Auxiliary Data

typedef struct cardano_auxiliary_data_t cardano_auxiliary_data_t

Auxiliary Data encapsulate certain optional information that can be attached to a transaction.

This data includes transaction metadata and scripts.

The Auxiliary Data is hashed and referenced in the transaction body.

cardano_error_t cardano_auxiliary_data_new(cardano_auxiliary_data_t **auxiliary_data)

Creates a new, empty auxiliary data object.

This function allocates and initializes a new cardano_auxiliary_data_t object, which can be used to hold transaction metadata or scripts that are included as auxiliary data in a Cardano transaction.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = NULL;
cardano_error_t result = cardano_auxiliary_data_new(&transaction_output);

if (result == CARDANO_SUCCESS)
{
  // Use the auxiliary data
  // Free resources when done
  cardano_auxiliary_data_unref(&transaction_output);
}
else
{
  printf("Failed to create the auxiliary data: %s\n", cardano_error_to_string(result));
}

Note

The caller is responsible for managing the lifecycle of the created auxiliary data object. When the auxiliary data object is no longer needed, the caller must release it by calling cardano_auxiliary_data_unref.

Parameters:
cardano_auxiliary_data_t **auxiliary_data

[out] A pointer to a location where the newly created cardano_auxiliary_data_t object will be stored. This parameter must not be NULL. On success, *auxiliary_data will point to the newly created auxiliary data object.

Returns:

CARDANO_SUCCESS if the auxiliary data object was successfully created, or an appropriate error code indicating the failure reason, such as CARDANO_ERROR_POINTER_IS_NULL if the auxiliary_data pointer is NULL, or CARDANO_ERROR_MEMORY_ALLOCATION_FAILED if memory allocation failed.

cardano_error_t cardano_auxiliary_data_from_cbor(cardano_cbor_reader_t *reader, cardano_auxiliary_data_t **auxiliary_data)

Creates a cardano_auxiliary_data_t from a CBOR reader.

This function parses CBOR data using a provided cardano_cbor_reader_t and constructs a cardano_auxiliary_data_t object. It assumes that the CBOR reader is set up correctly and that the CBOR data corresponds to the structure expected for a auxiliary_data.

Usage Example: 

cardano_cbor_reader_t* reader = cardano_cbor_reader_new(cbor_data, data_size);
cardano_auxiliary_data_t* auxiliary_data = NULL;

cardano_error_t result = cardano_auxiliary_data_from_cbor(reader, &auxiliary_data);

if (result == CARDANO_SUCCESS)
{
  // Use the auxiliary_data

  // Once done, ensure to clean up and release the auxiliary_data
  cardano_auxiliary_data_unref(&auxiliary_data);
}
else
{
  const char* error = cardano_cbor_reader_get_last_error(reader);
  printf("Failed to decode auxiliary_data: %s\n", error);
}

cardano_cbor_reader_unref(&reader); // Cleanup the CBOR reader

Remark

In Cardano, transactions are encoded in CBOR, but CBOR allows multiple valid ways to encode the same data. The Cardano blockchain does not enforce a canonical transaction representation, meaning that if you decode a transaction from CBOR and then re-encode it, the resulting encoding could be different. This would change the auxiliary data hash and invalidate any existing signatures. To prevent this, when a transaction auxiliary data object is created using cardano_auxiliary_data_from_cbor, it caches the original CBOR representation internally. When cardano_auxiliary_data_to_cbor is called, it will output the cached CBOR. If the cached CBOR representation is not needed, the client can call cardano_auxiliary_data_clear_cbor_cache after the object has been created.

Note

If the function fails, the last error can be retrieved by calling cardano_cbor_reader_get_last_error with the reader. The caller is responsible for freeing the created cardano_auxiliary_data_t object by calling cardano_auxiliary_data_unref when it is no longer needed.

Parameters:
cardano_cbor_reader_t *reader

[in] A pointer to an initialized cardano_cbor_reader_t that is ready to read the CBOR-encoded data.

cardano_auxiliary_data_t **auxiliary_data

[out] A pointer to a pointer of cardano_auxiliary_data_t that will be set to the address of the newly created auxiliary_data object upon successful decoding.

Returns:

A cardano_error_t value indicating the outcome of the operation. Returns CARDANO_SUCCESS if the auxiliary data were successfully created, or an appropriate error code if an error occurred.

cardano_error_t cardano_auxiliary_data_to_cbor(const cardano_auxiliary_data_t *auxiliary_data, cardano_cbor_writer_t *writer)

Serializes auxiliary data into CBOR format using a CBOR writer.

This function serializes the given cardano_auxiliary_data_t object using a cardano_cbor_writer_t.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...;
cardano_cbor_writer_t* writer = cardano_cbor_writer_new();

if (writer)
{
  cardano_error_t result = cardano_auxiliary_data_to_cbor(auxiliary_data, writer);

  if (result == CARDANO_SUCCESS)
  {
    // Use the writer's buffer containing the serialized data
  }
  else
  {
    const char* error_message = cardano_cbor_writer_get_last_error(writer);
    printf("Serialization failed: %s\n", error_message);
  }

  cardano_cbor_writer_unref(&writer);
}

cardano_auxiliary_data_unref(&auxiliary_data);

Remark

If the auxiliary data object was created by cardano_auxiliary_data_from_cbor, the original CBOR encoding will be cached and reused by this function to prevent round-trip encoding issues that can change the auxiliary data hash and invalidate signatures.

Parameters:
const cardano_auxiliary_data_t *auxiliary_data

[in] A constant pointer to the cardano_auxiliary_data_t object that is to be serialized.

cardano_cbor_writer_t *writer

[out] A pointer to a cardano_cbor_writer_t where the CBOR serialized data will be written. The writer must already be initialized and ready to accept the data.

Returns:

Returns CARDANO_SUCCESS if the serialization is successful. If the auxiliary_data or writer is NULL, returns CARDANO_ERROR_POINTER_IS_NULL.

cardano_error_t cardano_auxiliary_data_to_cip116_json(const cardano_auxiliary_data_t *auxiliary_data, cardano_json_writer_t *writer)

Serializes auxiliary data to CIP-116 JSON.

This function writes a JSON object representing the auxiliary data using the CIP-116 shapes for each component:

The function writes the enclosing {} object. Properties that are not present (i.e., corresponding list or map is NULL or empty) are omitted.

Parameters:
const cardano_auxiliary_data_t *auxiliary_data

[in] A valid pointer to a cardano_auxiliary_data_t instance.

cardano_json_writer_t *writer

[in] A valid pointer to a cardano_json_writer_t positioned where a JSON value is expected.

Returns:

CARDANO_SUCCESS on success; an appropriate error code otherwise (e.g., CARDANO_ERROR_POINTER_IS_NULL for invalid arguments, or a downstream serialization error).

cardano_transaction_metadata_t *cardano_auxiliary_data_get_transaction_metadata(cardano_auxiliary_data_t *auxiliary_data)

Retrieves the transaction metadata from an auxiliary data object.

This function extracts the transaction metadata from a given cardano_auxiliary_data_t object.

Usage Example: 

// Assume auxiliary_data is already initialized and may contain metadata
cardano_auxiliary_data_t* auxiliary_data = ...;

// Retrieve the transaction metadata
cardano_transaction_metadata_t* metadata = cardano_auxiliary_data_get_transaction_metadata(auxiliary_data);

if (metadata != NULL)
{
  // Process the metadata
  // Release the metadata object when done
  cardano_transaction_metadata_unref(&metadata);
}
else
{
  printf("No transaction metadata present in the auxiliary data.\n");
}

Note

The transaction metadata is optional in an auxiliary data object. Always check the returned pointer for NULL before using it.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer to an initialized cardano_auxiliary_data_t object from which to retrieve the transaction metadata. This parameter must not be NULL.

Returns:

A pointer to a cardano_transaction_metadata_t object containing the transaction metadata. If the auxiliary data does not contain any transaction metadata, the function returns NULL. The returned object is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release it by calling cardano_transaction_metadata_unref when it is no longer needed.

cardano_error_t cardano_auxiliary_data_set_transaction_metadata(cardano_auxiliary_data_t *auxiliary_data, cardano_transaction_metadata_t *metadata)

Sets or unsets the transaction metadata for an auxiliary data object.

This function assigns the specified transaction metadata to a given cardano_auxiliary_data_t object. If the metadata parameter is NULL, it will remove any existing transaction metadata from the auxiliary data.

Usage Example: 

// Assume auxiliary_data and metadata are already initialized
cardano_auxiliary_data_t* auxiliary_data = ...;
cardano_transaction_metadata_t* metadata = ...;

// Set the transaction metadata for the auxiliary data object
cardano_error_t result = cardano_auxiliary_data_set_transaction_metadata(auxiliary_data, metadata);

if (result == CARDANO_SUCCESS)
{
  printf("Transaction metadata successfully set.\n");
}
else
{
  printf("Failed to set transaction metadata: %s\n", cardano_error_to_string(result));
}

// Unset the transaction metadata by passing NULL
result = cardano_auxiliary_data_set_transaction_metadata(auxiliary_data, NULL);

if (result == CARDANO_SUCCESS)
{
  printf("Transaction metadata successfully unset.\n");
}
else
{
  printf("Failed to unset transaction metadata: %s\n", cardano_error_to_string(result));
}

Note

If metadata is not NULL, this function increases the reference count of the metadata object, meaning that the caller retains ownership of their reference and is responsible for managing its lifecycle. The caller must ensure that the cardano_transaction_metadata_unref function is called when the metadata object is no longer needed. If metadata is NULL, any existing metadata in the auxiliary data will be removed.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[inout] A pointer to an initialized cardano_auxiliary_data_t object to which the transaction metadata will be set or unset. This parameter must not be NULL.

cardano_transaction_metadata_t *metadata

[in] A pointer to an initialized cardano_transaction_metadata_t object containing the metadata to be associated with the auxiliary data, or NULL to unset the metadata.

Returns:

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the metadata was successfully set or unset, or an appropriate error code indicating the failure reason, such as CARDANO_ERROR_POINTER_IS_NULL if the auxiliary_data pointer is NULL.

cardano_native_script_list_t *cardano_auxiliary_data_get_native_scripts(cardano_auxiliary_data_t *auxiliary_data)

Retrieves the list of native scripts from auxiliary data.

This function extracts and returns a list of native scripts from the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_native_script_list_t* native_scripts = cardano_auxiliary_data_get_native_scripts(auxiliary_data);

if (native_scripts != NULL)
{
  // Use the native scripts

  // Ensure to release the native script list when done
  cardano_native_script_list_unref(&native_scripts);
}
else
{
  printf("No native scripts found in auxiliary data.\n");
}

Note

The returned native script list, if present, is a new reference, meaning the caller must manage the memory for this object. If the auxiliary data contains no native scripts, the function will return NULL, and the caller should handle this case appropriately.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer of an initialized cardano_auxiliary_data_t object from which the native scripts will be retrieved. This parameter must not be NULL.

Returns:

A pointer to a cardano_native_script_list_t object representing the list of native scripts. If the auxiliary data does not contain any native scripts, this function returns NULL. The returned list is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release the list by calling cardano_native_script_list_unref when it is no longer needed.

Returns:

Returns CARDANO_SUCCESS if the native scripts were successfully retrieved, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_auxiliary_data_set_native_scripts(cardano_auxiliary_data_t *auxiliary_data, cardano_native_script_list_t *scripts)

Sets the list of native scripts in auxiliary data.

This function assigns a list of native scripts to the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_native_script_list_t* native_scripts = ...; // Assume native_scripts is initialized

cardano_error_t result = cardano_auxiliary_data_set_native_scripts(auxiliary_data, native_scripts);

if (result == CARDANO_SUCCESS)
{
  printf("Native scripts successfully set in auxiliary data.\n");
}
else
{
  printf("Failed to set native scripts: %s\n", cardano_error_to_string(result));
}

// Clean up resources when done
cardano_native_script_list_unref(&native_scripts);

Note

If the scripts parameter is NULL, any existing native scripts in the auxiliary data will be removed. The caller is responsible for managing the memory for the scripts object; this function will increment the reference count of the scripts object if provided.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[inout] A pointer to an initialized cardano_auxiliary_data_t object where the native scripts will be set.

cardano_native_script_list_t *scripts

[in] A pointer to a cardano_native_script_list_t object representing the list of native scripts to be added. This parameter can be NULL to unset the native scripts in the auxiliary data.

Returns:

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the native scripts were successfully set, or an appropriate error code if an error occurred, such as CARDANO_ERROR_POINTER_IS_NULL if any required pointers are NULL.

cardano_plutus_v1_script_list_t *cardano_auxiliary_data_get_plutus_v1_scripts(cardano_auxiliary_data_t *auxiliary_data)

Retrieves the list of plutus v1 scripts from auxiliary data.

This function extracts and returns a list of plutus v1 scripts from the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_plutus_v1_script_list_t* plutus_v1_scripts = cardano_auxiliary_data_get_plutus_v1_scripts(auxiliary_data);

if (plutus_v1_scripts != NULL)
{
  // Use the plutus v1 scripts

  // Ensure to release the plutus v1 script list when done
  cardano_plutus_v1_script_list_unref(&plutus_v1_scripts);
}
else
{
  printf("No plutus v1 scripts found in auxiliary data.\n");
}

Note

The returned plutus v1 script list, if present, is a new reference, meaning the caller must manage the memory for this object. If the auxiliary data contains no plutus v1 scripts, the function will return NULL, and the caller should handle this case appropriately.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer of an initialized cardano_auxiliary_data_t object from which the plutus v1 scripts will be retrieved. This parameter must not be NULL.

Returns:

A pointer to a cardano_plutus_v1_script_list_t object representing the list of plutus v1 scripts. If the auxiliary data does not contain any plutus v1 scripts, this function returns NULL. The returned list is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release the list by calling cardano_plutus_v1_script_list_unref when it is no longer needed.

Returns:

Returns CARDANO_SUCCESS if the plutus v1 scripts were successfully retrieved, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_auxiliary_data_set_plutus_v1_scripts(cardano_auxiliary_data_t *auxiliary_data, cardano_plutus_v1_script_list_t *scripts)

Sets the list of plutus v1 scripts in auxiliary data.

This function assigns a list of plutus v1 scripts to the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_plutus_v1_script_list_t* plutus_v1_scripts = ...; // Assume plutus_v1_scripts is initialized

cardano_error_t result = cardano_auxiliary_data_set_plutus_v1_scripts(auxiliary_data, plutus_v1_scripts);

if (result == CARDANO_SUCCESS)
{
  printf("Native scripts successfully set in auxiliary data.\n");
}
else
{
  printf("Failed to set plutus v1 scripts: %s\n", cardano_error_to_string(result));
}

// Clean up resources when done
cardano_plutus_v1_script_list_unref(&plutus_v1_scripts);

Note

If the scripts parameter is NULL, any existing plutus v1 scripts in the auxiliary data will be removed. The caller is responsible for managing the memory for the scripts object; this function will increment the reference count of the scripts object if provided.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[inout] A pointer to an initialized cardano_auxiliary_data_t object where the plutus v1 scripts will be set.

cardano_plutus_v1_script_list_t *scripts

[in] A pointer to a cardano_plutus_v1_script_list_t object representing the list of plutus v1 scripts to be added. This parameter can be NULL to unset the plutus v1 scripts in the auxiliary data.

Returns:

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the plutus v1 scripts were successfully set, or an appropriate error code if an error occurred, such as CARDANO_ERROR_POINTER_IS_NULL if any required pointers are NULL.

cardano_plutus_v2_script_list_t *cardano_auxiliary_data_get_plutus_v2_scripts(cardano_auxiliary_data_t *auxiliary_data)

Retrieves the list of plutus v2 scripts from auxiliary data.

This function extracts and returns a list of plutus v2 scripts from the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_plutus_v2_script_list_t* plutus_v2_scripts = cardano_auxiliary_data_get_plutus_v2_scripts(auxiliary_data);

if (plutus_v2_scripts != NULL)
{
  // Use the plutus v2 scripts

  // Ensure to release the plutus v2 script list when done
  cardano_plutus_v2_script_list_unref(&plutus_v2_scripts);
}
else
{
  printf("No plutus v2 scripts found in auxiliary data.\n");
}

Note

The returned plutus v2 script list, if present, is a new reference, meaning the caller must manage the memory for this object. If the auxiliary data contains no plutus v2 scripts, the function will return NULL, and the caller should handle this case appropriately.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer of an initialized cardano_auxiliary_data_t object from which the plutus v2 scripts will be retrieved. This parameter must not be NULL.

Returns:

A pointer to a cardano_plutus_v2_script_list_t object representing the list of plutus v2 scripts. If the auxiliary data does not contain any plutus v2 scripts, this function returns NULL. The returned list is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release the list by calling cardano_plutus_v2_script_list_unref when it is no longer needed.

Returns:

Returns CARDANO_SUCCESS if the plutus v2 scripts were successfully retrieved, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_auxiliary_data_set_plutus_v2_scripts(cardano_auxiliary_data_t *auxiliary_data, cardano_plutus_v2_script_list_t *scripts)

Sets the list of plutus v2 scripts in auxiliary data.

This function assigns a list of plutus v2 scripts to the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_plutus_v2_script_list_t* plutus_v2_scripts = ...; // Assume plutus_v2_scripts is initialized

cardano_error_t result = cardano_auxiliary_data_set_plutus_v2_scripts(auxiliary_data, plutus_v2_scripts);

if (result == CARDANO_SUCCESS)
{
  printf("Native scripts successfully set in auxiliary data.\n");
}
else
{
  printf("Failed to set plutus v2 scripts: %s\n", cardano_error_to_string(result));
}

// Clean up resources when done
cardano_plutus_v2_script_list_unref(&plutus_v2_scripts);

Note

If the scripts parameter is NULL, any existing plutus v2 scripts in the auxiliary data will be removed. The caller is responsible for managing the memory for the scripts object; this function will increment the reference count of the scripts object if provided.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[inout] A pointer to an initialized cardano_auxiliary_data_t object where the plutus v2 scripts will be set.

cardano_plutus_v2_script_list_t *scripts

[in] A pointer to a cardano_plutus_v2_script_list_t object representing the list of plutus v2 scripts to be added. This parameter can be NULL to unset the plutus v2 scripts in the auxiliary data.

Returns:

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the plutus v2 scripts were successfully set, or an appropriate error code if an error occurred, such as CARDANO_ERROR_POINTER_IS_NULL if any required pointers are NULL.

cardano_plutus_v3_script_list_t *cardano_auxiliary_data_get_plutus_v3_scripts(cardano_auxiliary_data_t *auxiliary_data)

Retrieves the list of plutus v3 scripts from auxiliary data.

This function extracts and returns a list of plutus v3 scripts from the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_plutus_v3_script_list_t* plutus_v3_scripts = cardano_auxiliary_data_get_plutus_v3_scripts(auxiliary_data);

if (plutus_v3_scripts != NULL)
{
  // Use the plutus v3 scripts

  // Ensure to release the plutus v3 script list when done
  cardano_plutus_v3_script_list_unref(&plutus_v3_scripts);
}
else
{
  printf("No plutus v3 scripts found in auxiliary data.\n");
}

Note

The returned plutus v3 script list, if present, is a new reference, meaning the caller must manage the memory for this object. If the auxiliary data contains no plutus v3 scripts, the function will return NULL, and the caller should handle this case appropriately.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer of an initialized cardano_auxiliary_data_t object from which the plutus v3 scripts will be retrieved. This parameter must not be NULL.

Returns:

A pointer to a cardano_plutus_v3_script_list_t object representing the list of plutus v3 scripts. If the auxiliary data does not contain any plutus v3 scripts, this function returns NULL. The returned list is a new reference, and the caller is responsible for managing its lifecycle. Specifically, the caller must release the list by calling cardano_plutus_v3_script_list_unref when it is no longer needed.

Returns:

Returns CARDANO_SUCCESS if the plutus v3 scripts were successfully retrieved, or an appropriate error code indicating the failure reason.

cardano_error_t cardano_auxiliary_data_set_plutus_v3_scripts(cardano_auxiliary_data_t *auxiliary_data, cardano_plutus_v3_script_list_t *scripts)

Sets the list of plutus v3 scripts in auxiliary data.

This function assigns a list of plutus v3 scripts to the specified cardano_auxiliary_data_t object.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume initialized
cardano_plutus_v3_script_list_t* plutus_v3_scripts = ...; // Assume plutus_v3_scripts is initialized

cardano_error_t result = cardano_auxiliary_data_set_plutus_v3_scripts(auxiliary_data, plutus_v3_scripts);

if (result == CARDANO_SUCCESS)
{
  printf("Native scripts successfully set in auxiliary data.\n");
}
else
{
  printf("Failed to set plutus v3 scripts: %s\n", cardano_error_to_string(result));
}

// Clean up resources when done
cardano_plutus_v3_script_list_unref(&plutus_v3_scripts);

Note

If the scripts parameter is NULL, any existing plutus v3 scripts in the auxiliary data will be removed. The caller is responsible for managing the memory for the scripts object; this function will increment the reference count of the scripts object if provided.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[inout] A pointer to an initialized cardano_auxiliary_data_t object where the plutus v3 scripts will be set.

cardano_plutus_v3_script_list_t *scripts

[in] A pointer to a cardano_plutus_v3_script_list_t object representing the list of plutus v3 scripts to be added. This parameter can be NULL to unset the plutus v3 scripts in the auxiliary data.

Returns:

cardano_error_t indicating the outcome of the operation. Returns CARDANO_SUCCESS if the plutus v3 scripts were successfully set, or an appropriate error code if an error occurred, such as CARDANO_ERROR_POINTER_IS_NULL if any required pointers are NULL.

cardano_blake2b_hash_t *cardano_auxiliary_data_get_hash(cardano_auxiliary_data_t *auxiliary_data)

Retrieves the hash of a auxiliary data.

This function computes and returns the hash of the given cardano_auxiliary_data_t object. The hash is a unique identifier for the auxiliary data.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = ...; // Assume auxiliary_data is already initialized
cardano_blake2b_hash_t* tx_body_hash = cardano_auxiliary_data_get_hash(auxiliary_data);

if (tx_body_hash != NULL)
{
  // Use the auxiliary data hash for signing or verification

  // Clean up when done
  cardano_blake2b_hash_unref(&tx_body_hash);
}
else
{
  printf("Failed to retrieve the auxiliary data hash.\n");
}

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer to an initialized cardano_auxiliary_data_t object. The object must be valid and not NULL.

Returns:

A pointer to a cardano_blake2b_hash_t object representing the auxiliary data hash. The returned object is a new reference, and the caller is responsible for releasing it by calling cardano_blake2b_hash_unref when it is no longer needed. If the input is NULL, the function will return NULL.

void cardano_auxiliary_data_clear_cbor_cache(cardano_auxiliary_data_t *auxiliary_data)

Clears the cached CBOR representation from a auxiliary data.

This function removes the internally cached CBOR data from a cardano_auxiliary_data_t object. It is useful when you have modified the auxiliary data after it was created from CBOR using cardano_auxiliary_data_from_cbor and you want to ensure that the next serialization reflects the current state of the auxiliary data, rather than using the original cached CBOR.

Usage Example: 

// Assume auxiliary_data was created using cardano_auxiliary_data_from_cbor
cardano_auxiliary_data_t* auxiliary_data = ...;

// Modify the auxiliary data as needed

// Clear the CBOR cache to ensure serialization uses the updated auxiliary data
cardano_auxiliary_data_clear_cbor_cache(auxiliary_data);

// Serialize the auxiliary data to CBOR
cardano_cbor_writer_t* writer = cardano_cbor_writer_new();

result = cardano_auxiliary_data_to_cbor(auxiliary_data, writer);

if (result == CARDANO_SUCCESS)
{
  // Process the CBOR data as needed
}
else
{
  const char* error_message = cardano_cbor_writer_get_last_error(writer);
  printf("Serialization failed: %s\n", error_message);
}

// Clean up resources
cardano_cbor_writer_unref(&writer);
cardano_auxiliary_data_unref(&auxiliary_data);

Warning

Clearing the CBOR cache may change the binary representation of the auxiliary data when serialized, which can alter the auxiliary data hash and invalidate any existing signatures. Use this function with caution, especially if the transaction has already been signed or if preserving the exact CBOR encoding is important for your application.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[inout] A pointer to an initialized cardano_auxiliary_data_t object from which the CBOR cache will be cleared.

void cardano_auxiliary_data_unref(cardano_auxiliary_data_t **auxiliary_data)

Decrements the reference count of a cardano_auxiliary_data_t object.

This function is responsible for managing the lifecycle of a cardano_auxiliary_data_t object by decreasing its reference count. When the reference count reaches zero, the auxiliary_data is finalized; its associated resources are released, and its memory is deallocated.

Usage Example: 

cardano_auxiliary_data_t* auxiliary_data = cardano_auxiliary_data_new(major, minor);

// Perform operations with the auxiliary_data...

cardano_auxiliary_data_unref(&auxiliary_data);
// At this point, auxiliary_data is NULL and cannot be used.

Note

After calling cardano_auxiliary_data_unref, the pointer to the cardano_auxiliary_data_t object will be set to NULL to prevent its reuse.

Parameters:
cardano_auxiliary_data_t **auxiliary_data

[inout] A pointer to the pointer of the auxiliary_data object. This double indirection allows the function to set the caller’s pointer to NULL, avoiding dangling pointer issues after the object has been freed.

void cardano_auxiliary_data_ref(cardano_auxiliary_data_t *auxiliary_data)

Increases the reference count of the cardano_auxiliary_data_t object.

This function is used to manually increment the reference count of an cardano_auxiliary_data_t object, indicating that another part of the code has taken ownership of it. This ensures the object remains allocated and valid until all owners have released their reference by calling cardano_auxiliary_data_unref.

Usage Example: 

// Assuming auxiliary_data is a previously created auxiliary_data object

cardano_auxiliary_data_ref(auxiliary_data);

// Now auxiliary_data can be safely used elsewhere without worrying about premature deallocation

Note

Always ensure that for every call to cardano_auxiliary_data_ref there is a corresponding call to cardano_auxiliary_data_unref to prevent memory leaks.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

A pointer to the cardano_auxiliary_data_t object whose reference count is to be incremented.

size_t cardano_auxiliary_data_refcount(const cardano_auxiliary_data_t *auxiliary_data)

Retrieves the current reference count of the cardano_auxiliary_data_t object.

This function returns the number of active references to an cardano_auxiliary_data_t object. It’s useful for debugging purposes or managing the lifecycle of the object in complex scenarios.

Usage Example: 

// Assuming auxiliary_data is a previously created auxiliary_data object

size_t ref_count = cardano_auxiliary_data_refcount(auxiliary_data);

printf("Reference count: %zu\n", ref_count);

Warning

This function does not account for transitive references. A transitive reference occurs when an object holds a reference to another object, rather than directly to the cardano_auxiliary_data_t. As such, the reported count may not fully represent the total number of conceptual references in cases where such transitive relationships exist.

Parameters:
const cardano_auxiliary_data_t *auxiliary_data

A pointer to the cardano_auxiliary_data_t object whose reference count is queried. The object must not be NULL.

Returns:

The number of active references to the specified cardano_auxiliary_data_t object. If the object is properly managed (i.e., every cardano_auxiliary_data_ref call is matched with a cardano_auxiliary_data_unref call), this count should reach zero right before the object is deallocated.

void cardano_auxiliary_data_set_last_error(cardano_auxiliary_data_t *auxiliary_data, const char *message)

Sets the last error message for a given cardano_auxiliary_data_t object.

Records an error message in the auxiliary_data’s last_error buffer, overwriting any existing message. This is useful for storing descriptive error information that can be later retrieved. The message is truncated if it exceeds the buffer’s capacity.

Note

The error message is limited to 1023 characters, including the null terminator, due to the fixed size of the last_error buffer.

Parameters:
cardano_auxiliary_data_t *auxiliary_data

[in] A pointer to the cardano_auxiliary_data_t instance whose last error message is to be set. If NULL, the function does nothing.

const char *message

[in] A null-terminated string containing the error message. If NULL, the auxiliary_data’s last_error is set to an empty string, indicating no error.

const char *cardano_auxiliary_data_get_last_error(const cardano_auxiliary_data_t *auxiliary_data)

Retrieves the last error message recorded for a specific auxiliary_data.

This function returns a pointer to the null-terminated string containing the last error message set by cardano_auxiliary_data_set_last_error for the given auxiliary_data. If no error message has been set, or if the last_error buffer was explicitly cleared, an empty string is returned, indicating no error.

Note

The returned string points to internal storage within the object and must not be modified by the caller. The string remains valid until the next call to cardano_auxiliary_data_set_last_error for the same auxiliary_data, or until the auxiliary_data is deallocated.

Parameters:
const cardano_auxiliary_data_t *auxiliary_data

[in] A pointer to the cardano_auxiliary_data_t instance whose last error message is to be retrieved. If the auxiliary_data is NULL, the function returns a generic error message indicating the null auxiliary_data.

Returns:

A pointer to a null-terminated string containing the last error message for the specified auxiliary_data. If the auxiliary_data is NULL, “Object is NULL.” is returned to indicate the error.