DNS Resolver library (libgetdns, -lgetdns)
getdns_hostname (getdns_context *context,
getdns_hostname_sync (getdns_context *context,
The getdns_hostname(3) and getdns_hostname_sync functions provide public entry points into the getdns API library to retrieve the host name given an address.
context A pointer to the previously created DNS context that is to be used with this DNS request. see getdns_context (3)
address a getdns_dict structure containing two names: address_type (whose value is bindata and is either "IPv4" or "IPv6") and address_data whose value is bindata
extensions extensions for this request, NULL if no extensions, see libgetdns (3) for a detailed description of extensions
userarg returned to the callback function untouched, can be NULL
transaction_id populated by the API and used to identify the callback (for example to getdns_cancel_callback), can be NULL, set to 0 if the function fails
callbackfn non-NULL pointer to a callback function defined by the application, typically used to process the response. Only the asynchronous signature accepts a callback function, the synchronous signature does not include a callback. See libgetdns (3) for a more detailed discussion of callback functions.
response A getdns_dict type is returned in response and always contains at least three names: replies_full (a list containing the DNS response as binary data), replies_tree (a list containing the parsed DNS response data) and status (an int). The storage associated with this must be freed by a call to getdns_free_sync_request_memory (3).
Upon successful completion the functions return GETDNS_RETURN_GOOD , otherwise the following error values are returned:
GETDNS_RETURN_BAD_CONTEXT if the context pointer is invalid or the context has internal deficiencies
GETDNS_RETURN_BAD_DOMAIN_NAME if the domain name passed to the function is invalid
GETDNS_RETURN_EXTENSION_MISFORMAT if the data type specified in one or more of the extensions does not match the specifications
GETDNS_RETURN_GENERIC_ERROR if some problem was encountered in the function not addressed by one of the more specific return codes
GETDNS_RETURN_INVALID PARAMETER if one or more parameters has an invalid value
GETDNS_RETURN_MEMORY_ERROR if unable to allocate the memory required
GETDNS_RETURN_NO_SUCH_EXTENSION if one or more of the strings specified in the extensions are not valid
The values of status included in the response parameter are:
GETDNS_RESPSTATUS_GOOD if at least one response was returned
GETDNS_RESPSTATUS_NO_NAME if queries for the name yielded all negative responses
GETDNS_RESPSTATUS_ALL_TIMEOUT if all queries for the name timed out
GETDNS_RESPSTATUS_NO_SECURE_ANSWERS if only secure replies accepted (per context) and at least one response was received but no DNS responses were secure through DNSSEC
For a more detailed explanation of the response object see libgetdns (3)
libgetdns(3), getdns_context(3), getdns_free_sync_request_memory(3), getdns_general(3), getdns_address(3), getdns_service(3),
getdns_address(3), getdns_cancel_callback(3), getdns_context(3), getdns_context_set_append_name(3), getdns_dict_get(3), getdns_dict_set(3), getdns_general(3), getdns_list_get(3), getdns_list_set(3), getdns_service(3), libgetdns(3).
The man page getdns_hostname_sync(3) is an alias of getdns_hostname(3).