Scheduling asynchronous requests

Typedefs
typedef void(*	getdns_callback_t) (getdns_context *context, getdns_callback_type_t callback_type, getdns_dict *response, void *userarg, getdns_transaction_t transaction_id)

Functions
getdns_return_t	getdns_general (getdns_context *context, const char *name, uint16_t request_type, const getdns_dict *extensions, void *userarg, getdns_transaction_t *transaction_id, getdns_callback_t callbackfn)
getdns_return_t	getdns_address (getdns_context *context, const char *name, const getdns_dict *extensions, void *userarg, getdns_transaction_t *transaction_id, getdns_callback_t callbackfn)
getdns_return_t	getdns_hostname (getdns_context *context, const getdns_dict *address, const getdns_dict *extensions, void *userarg, getdns_transaction_t *transaction_id, getdns_callback_t callbackfn)
getdns_return_t	getdns_service (getdns_context *context, const char *name, const getdns_dict *extensions, void *userarg, getdns_transaction_t *transaction_id, getdns_callback_t callbackfn)
getdns_return_t	getdns_cancel_callback (getdns_context *context, getdns_transaction_t transaction_id)

Detailed Description

Typedef Documentation

getdns_callback_t

typedef void(* getdns_callback_t) (getdns_context *context, getdns_callback_type_t callback_type, getdns_dict *response, void *userarg, getdns_transaction_t transaction_id)

The type of the callback function that must be registered when scheduling asynchronous requests. The registered function will be called from the eventloop with the following parameters.

See also

Callback types and texts

Parameters

context	The DNS context that was used in the calling function
callback_type	Supplies the reason for the callback. This will be one of: GETDNS_CALLBACK_COMPLETE The response has the requested data in it GETDNS_CALLBACK_CANCEL The calling program cancelled the callback; response is NULL GETDNS_CALLBACK_TIMEOUT The requested action timed out; response is filled in with empty structures or will contain additional information about the timeout when used in combination with the return_call_reporting extension. GETDNS_CALLBACK_ERROR The requested action had an error; response is NULL.
response	A response object with the response data. The application is responsible for cleaning up the response object with getdns_dict_destroy.
userarg	Identical to the userarg passed to the calling function.
transaction_id	The transaction identifier that was assigned by the calling function.

Definition at line 1014 of file getdns.h.

Function Documentation

getdns_general()

getdns_return_t getdns_general	(	getdns_context *	context,
		const char *	name,
		uint16_t	request_type,
		const getdns_dict *	extensions,
		void *	userarg,
		getdns_transaction_t *	transaction_id,
		getdns_callback_t	callbackfn
	)

retrieve general DNS data

See also

RR Types

getdns_general_sync

Parameters

	context	pointer to a previously created context to be used for this call
	name	the ASCII based domain name to lookup
	request_type	RR type for the query, e.g. GETDNS_RR_TYPE_NS
	extensions	dict data structures, NULL to use no extensions
	userarg	void* returned to the callback untouched
[out]	transaction_id	id used to identify the callback, NULL is ignored
	callbackfn	callback function defined by the application

Returns

GETDNS_RETURN_GOOD on success

getdns_address()

getdns_return_t getdns_address	(	getdns_context *	context,
		const char *	name,
		const getdns_dict *	extensions,
		void *	userarg,
		getdns_transaction_t *	transaction_id,
		getdns_callback_t	callbackfn
	)

retrieve address assigned to a DNS name

See also

getdns_address_sync

Parameters

	context	pointer to a previously created context to be used for this call
	name	the ASCII based domain name to lookup
	extensions	dict data structures, NULL to use no extensions
	userarg	void* returned to the callback untouched
[out]	transaction_id	id used to identify the callback, NULL is ignored
	callbackfn	callback function defined by the application

Returns

GETDNS_RETURN_GOOD on success

getdns_hostname()

getdns_return_t getdns_hostname	(	getdns_context *	context,
		const getdns_dict *	address,
		const getdns_dict *	extensions,
		void *	userarg,
		getdns_transaction_t *	transaction_id,
		getdns_callback_t	callbackfn
	)

retrieve hostname assigned to an IP address

See also

getdns_hostname_sync

Parameters

	context	pointer to a previously created context to be used for this call
	address	the address to look up
	extensions	dict data structures, NULL to use no extensions
	userarg	void* returned to the callback untouched
[out]	transaction_id	id used to identify the callback, NULL is ignored
	callbackfn	callback function defined by the application

Returns

GETDNS_RETURN_GOOD on success

getdns_service()

getdns_return_t getdns_service	(	getdns_context *	context,
		const char *	name,
		const getdns_dict *	extensions,
		void *	userarg,
		getdns_transaction_t *	transaction_id,
		getdns_callback_t	callbackfn
	)

retrieve a service assigned to a DNS name

See also

getdns_service_sync

Parameters

	context	pointer to a previously created context to be used for this call
	name	the ASCII based domain name to lookup
	extensions	dict data structures, NULL to use no extensions
	userarg	void* returned to the callback untouched
[out]	transaction_id	id used to identify the callback, NULL is ignored
	callbackfn	callback function defined by the application

Returns

GETDNS_RETURN_GOOD on success

getdns_cancel_callback()

getdns_return_t getdns_cancel_callback	(	getdns_context *	context,
		getdns_transaction_t	transaction_id
	)

Cancel an outstanding asynchronous request. The callback registered with the request will be called with the getdns_callback_type_t set to GETDNS_CALLBACK_CANCEL and the response set to NULL.