EVT_BACNET_SUBSCRIBECOV (STRUCT)

TYPE EVT_BACNET_SUBSCRIBECOV : STRUCT

The SubscribeCOV service hook

This is the type declaration for the Subscribe COV service application hook. This hook allows a BACnet application to process this service. This hook is given all of the parameters of a service request, and is responsible for all error checking (Device/Object existence and so forth). A pointer to the routine is registered with the BACnet server by BACnetSetHook API routine. A hook can be registered by the registering API routine at any time. One hook procedure is registered per service. If a hook is registered more than once for the same service, the new hook procedure replaces the old one. A 0 procedure pointer can be used to deregister the hook. A Subscribe COV hook must complete its service request processing by using one of the transaction completion API routines: BACnetSrvcAbortCbCompletion, BACnetSrvcErrorCbCompletion, BACnetSrvcIgnoreCbCompletion, or BACnetSrvcRejectCbCompletion. Hooks can access the local Properties maintained in the API database by using the BACnetStorePropertyInstance / BACnetRetrievePropertyInstance routines. A hook can choose not to override the default API processing of a service request by returning the value CB_STATUS_DEFAULT.

InOut:

Name	Type	Comment
pCBStatus	POINTER TO IEC_BACNET_CB_STATUS	CB-Status returned for the event. “Default” processes the standard APIs reaction, which needs no additional Callback-Signalling.
phTransaction	POINTER TO BYTE	This is the Transaction State Machine (TSM) handle for the current service request. It is generated by the BACnet API and is the first parameter given to the Hook- Completion functions.
sourceAddress	POINTER TO IEC_BACNET_ADDRESS	This is the MAC address of the BACnet addressed device from which the request has been sent.
destinationAddress	POINTER TO IEC_BACNET_ADDRESS	This is the MAC address of the device constructed by the application which has received the request.
pServiceInfo	POINTER TO IEC_BACNET_SUBSCRIBE_COV_INFO	A pointer to the service information data structure.