BACnetSubscribeCOV (FUN)

FUNCTION BACnetSubscribeCOV : IEC_BACNET_STATUS

Sends an SubscribeCov request

Sends a message to subscribe a COV client to receive COV notifications from a BACnet standard object, or cancel the existing subscription. If the standard object supports COV reporting, COV notification may be sent to one or more subscriber clients. A subscription establishes a connection between the change of value detection and reporting mechanism within the COV-server device, and a logical Process within a COV-client. This routine may control APDU properties like APDU length, segmentation, and timeout for both request and in response. This routine can execute asynchronously, i.e. this routine will return to the caller before the BACnet reply comes so that the applications can keep running. In this case the response information will be received by the thread which is responsible for receiving asynchronous responses. An optional BACNET_SIMPLE_ACK_COMPLETE_CB routine, which is provided by the BACnet application, shall be used to process this information. If a number of asynchronous requests are sent, the responses shall be queued and identified by the transaction handles. If the application does not supply the BACNET_SIMPLE_ACK_COMPLETE_CB routine then the BACnetSubscribeCOV routine sends a request and waits for the reply.

InOut:

Scope	Name	Type	Comment
Return	BACnetSubscribeCOV	IEC_BACNET_STATUS	A status indicating whether the operation worked.
Input	pSourceAddress	POINTER TO IEC_BACNET_ADDRESS	If the BACnet application has only one device constructed and installed, this can be 0. In this case the MAC address of this device will be used. Otherwise this shall be the MAC address returned on device object construction.
	pDestinationAddress	POINTER TO IEC_BACNET_ADDRESS	This is the MAC address of the device to which the request should be sent.
	pSubscriber	POINTER TO IEC_BACNET_SUBSCRIBE_COV_INFO	A pointer to a memory block which contains data structure defining a set of parameters: whether this request is for subscription or cancellation, the destination Process identifier, monitored object identifier, whether confirmed or unconfirmed notification is required, and subscription lifetime.
	pAPDUParams	POINTER TO IEC_BACNET_APDU_PROPERTIES	A pointer to the APDU-Properties structure which sets APDU properties for this transaction only. This does not change global defaults or settings for the application APDU Properties. This argument may be 0. In this case APDU properties are used which were specified in the device object properties of the applications device which sends the request.
	pTransactionToken	POINTER TO BACnetAsyncTransactionToken	Transaction token of the asynchronous call - see BACnetAsyncTransactionToken.
	pError	POINTER TO IEC_BACNET_ERROR	A pointer to a structure to hold BACnet Error information. pError may be 0 if the application isn’t interested in detailed error information.