Built-in Topics

Built-in objects created by RTI Connext but accessible to the application. More...

Modules
	Participant Built-in Topics
	Builtin topic for accessing information about the DomainParticipants discovered by RTI Connext.
	Topic Built-in Topics
	Builtin topic for accessing information about the Topics discovered by RTI Connext.
	Publication Built-in Topics
	Builtin topic for accessing information about the Publications discovered by RTI Connext.
	Subscription Built-in Topics
	Builtin topic for accessing information about the Subscriptions discovered by RTI Connext.
	ServiceRequest Built-in Topic
	Builtin topic for accessing requests from different services within RTI Connext.
	Common types and functions
	Types and functions related to the built-in topics.

Detailed Description

Built-in objects created by RTI Connext but accessible to the application.

RTI Connext must discover and keep track of the remote entities, such as new participants in the domain. This information may also be important to the application, which may want to react to this discovery, or else access it on demand.

A set of built-in topics and corresponding DDS_DataReader objects are introduced to be used by the application to access this discovery information.

The information can be accessed as if it were normal application data. This allows the application to know when there are any changes in those values by means of the DDS_Listener or the DDS_Condition mechanisms.

The built-in data-readers all belong to a built-in DDS_Subscriber, which can be retrieved by using the function DDS_DomainParticipant_get_builtin_subscriber. The built-in DDS_DataReader objects can be retrieved by using the operation DDS_Subscriber_lookup_datareader, with the topic name as a parameter.

Built-in entities have default listener settings as well. The built-in DDS_Subscriber and all of its built-in topics have 'nil' listeners with all statuses appearing in their listener masks (acting as a NO-OP listener that does not reset communication status). The built-in DataReaders have null listeners with no statuses in their masks.

The information that is accessible about the remote entities by means of the built-in topics includes all the QoS policies that apply to the corresponding remote Entity. These QoS policies appear as normal 'data' fields inside the data read by means of the built-in Topic. Additional information is provided to identify the Entity and facilitate the application logic.

The built-in DDS_DataReader will not provide data pertaining to entities created from the same DDS_DomainParticipant under the assumption that such entities are already known to the application that created them.

The discovery information provided by each built-in reader won't be received until it is first looked up. And if the DomainParticipant was created in a disabled state (see DDS_EntityFactoryQosPolicy), the built-in subscriber and readers will need to be enabled explicitly (by the DDS_Entity_enable operation).

Refer to DDS_ParticipantBuiltinTopicData, DDS_TopicBuiltinTopicData, DDS_SubscriptionBuiltinTopicData and DDS_PublicationBuiltinTopicData for a description of all the built-in topics and their contents.

The QoS of the built-in DDS_Subscriber and DDS_DataReader objects is given by the following table:

QoS of built-in DDS_Subscriber and DDS_DataReader

QoS	Value
DDS_UserDataQosPolicy	0-length sequence
DDS_TopicDataQosPolicy	0-length sequence
DDS_GroupDataQosPolicy	0-length sequence
DDS_DurabilityQosPolicy	DDS_TRANSIENT_LOCAL_DURABILITY_QOS
DDS_DurabilityServiceQosPolicy	Does not apply as DDS_DurabilityQosPolicyKind is DDS_TRANSIENT_LOCAL_DURABILITY_QOS
DDS_PresentationQosPolicy	access_scope = DDS_TOPIC_PRESENTATION_QOS coherent_access = DDS_BOOLEAN_FALSE ordered_access = DDS_BOOLEAN_FALSE
DDS_DeadlineQosPolicy	Period = infinite
DDS_LatencyBudgetQosPolicy	duration = 0
DDS_OwnershipQosPolicy	DDS_SHARED_OWNERSHIP_QOS
DDS_OwnershipStrengthQosPolicy	value = 0
DDS_LivelinessQosPolicy	kind = DDS_AUTOMATIC_LIVELINESS_QOS lease_duration = 0
DDS_TimeBasedFilterQosPolicy	minimum_separation = 0
DDS_PartitionQosPolicy	0-length sequence
DDS_ReliabilityQosPolicy	kind = DDS_RELIABLE_RELIABILITY_QOS max_blocking_time = 100 milliseconds
DDS_DestinationOrderQosPolicy	DDS_BY_RECEPTION_TIMESTAMP_DESTINATIONORDER_QOS
DDS_HistoryQosPolicy	kind = DDS_KEEP_LAST_HISTORY_QOS depth = 1
DDS_ResourceLimitsQosPolicy	max_samples = DDS_LENGTH_UNLIMITED max_instances = DDS_LENGTH_UNLIMITED max_samples_per_instance = DDS_LENGTH_UNLIMITED
DDS_ReaderDataLifecycleQosPolicy	autopurge_nowriter_samples_delay = infinite autopurge_disposed_samples_delay = infinite
DDS_EntityFactoryQosPolicy	autoenable_created_entities = DDS_BOOLEAN_TRUE