Asynchronous Messaging

Structure for managing asynchronous state of CoAP resources. More...

Data Structures
struct	coap_async_state_t

Macros
#define	COAP_ASYNC_CONFIRM   0x01
	send confirmable response More...
#define	COAP_ASYNC_SEPARATE   0x02
	send separate response More...
#define	COAP_ASYNC_OBSERVED   0x04
	the resource is being observed More...
#define	COAP_ASYNC_RELEASE_DATA   0x08
	release application data on destruction More...

Typedefs
typedef struct coap_async_state_t	coap_async_state_t

Functions
coap_async_state_t *	coap_register_async (coap_context_t *context, coap_address_t *peer, coap_pdu_t *request, unsigned char flags, void *data)
	Allocates a new coap_async_state_t object and fills its fields according to the given request. More...
int	coap_remove_async (coap_context_t *context, coap_tid_t id, coap_async_state_t **s)
	Removes the state object identified by id from context. More...
void	coap_free_async (coap_async_state_t *state)
	Releases the memory that was allocated by coap_async_state_init() for the object s. More...
coap_async_state_t *	coap_find_async (coap_context_t *context, coap_tid_t id)
	Retrieves the object identified by id from the list of asynchronous transactions that are registered with context. More...
static void	coap_touch_async (coap_async_state_t *s)
	Updates the time stamp of s. More...

Detailed Description

Structure for managing asynchronous state of CoAP resources.

A coap_resource_t object holds a list of coap_async_state_t objects that can be used to generate a separate response in case a result of an operation cannot be delivered in time, or the resource has been explicitly subscribed to with the option observe.

Macro Definition Documentation

#define COAP_ASYNC_CONFIRM   0x01

send confirmable response

Definition at line 59 of file async.h.

#define COAP_ASYNC_OBSERVED   0x04

the resource is being observed

Definition at line 61 of file async.h.

#define COAP_ASYNC_RELEASE_DATA   0x08

release application data on destruction

Definition at line 64 of file async.h.

#define COAP_ASYNC_SEPARATE   0x02

send separate response

Definition at line 60 of file async.h.

Typedef Documentation

typedef struct coap_async_state_t coap_async_state_t

Function Documentation

coap_async_state_t* coap_find_async	(	coap_context_t *	context,
		coap_tid_t	id
	)

Retrieves the object identified by id from the list of asynchronous transactions that are registered with context.

This function returns a pointer to that object or NULL if not found.

Parameters

context	The context where the asynchronous objects are registered with.
id	The id of the object to retrieve.

Returns

A pointer to the object identified by id or NULL if not found.

Definition at line 74 of file async.c.

void coap_free_async

(

coap_async_state_t *

state

)

Releases the memory that was allocated by coap_async_state_init() for the object s.

The registered application data will be released automatically if COAP_ASYNC_RELEASE_DATA is set.

Parameters

s	The object to delete.

Definition at line 93 of file async.c.

coap_async_state_t* coap_register_async	(	coap_context_t *	context,
		coap_address_t *	peer,
		coap_pdu_t *	request,
		unsigned char	flags,
		void *	data
	)

Allocates a new coap_async_state_t object and fills its fields according to the given request.

The flags are used to control generation of empty ACK responses to stop retransmissions and to release registered data when the resource is deleted by coap_free_async(). This function returns a pointer to the registered coap_async_t object or NULL on error. Note that this function will return NULL in case that an object with the same identifier is already registered.

Parameters

context	The context to use.
peer	The remote peer that is to be asynchronously notified.
request	The request that is handled asynchronously.
flags	Flags to control state management.
data	Opaque application data to register. Note that the storage occupied by data is released on destruction only if flag COAP_ASYNC_RELEASE_DATA is set.

Returns

A pointer to the registered coap_async_state_t object or NULL in case of an error.

Definition at line 25 of file async.c.

int coap_remove_async	(	coap_context_t *	context,
		coap_tid_t	id,
		coap_async_state_t **	s
	)

Removes the state object identified by id from context.

The removed object is returned in s, if found. Otherwise, s is undefined. This function returns 1 if the object was removed, 0 otherwise. Note that the storage allocated for the stored object is not released by this functions. You will have to call coap_free_async() to do so.

Parameters

context	The context where the async object is registered.
id	The identifier of the asynchronous transaction.
s	Will be set to the object identified by id after removal.

Returns

1 if object was removed and s updated, or 0 if no object was found with the given id. s is valid only if the return value is 1.

Definition at line 81 of file async.c.

static void coap_touch_async ( coap_async_state_t *  s )

inlinestatic

Updates the time stamp of s.

Parameters

s	The state object to update.

Definition at line 141 of file async.h.