Use these QoS fields to configure how much data, which data, and when that data is available to an application.

Data availability refers to configurations such as ownership and lifespan.


DDS_AvailabilityQosPolicy	enable_required_subscriptions
	<<extension>> Enables support for required subscriptions in a DDS_DataWriter

DDS_AvailabilityQosPolicy	max_data_availability_waiting_time
	<<extension>> Defines how much time to wait before delivering a sample to the application without having received some of the previous samples.

DDS_AvailabilityQosPolicy	max_endpoint_availability_waiting_time
	<<extension>> Defines how much time to wait to discover DataWriters providing samples for the same data source (virtual GUID).

DDS_AvailabilityQosPolicy	required_matched_endpoint_groups
	<<extension>> A sequence of endpoint groups.

DDS_DurabilityQosPolicy	kind
	<<basic>> <<spec>> The kind of durability.

DDS_DurabilityQosPolicy	direct_communication
	<<extension>> Indicates whether or not a TRANSIENT or PERSISTENT DDS_DataReader should receive samples directly from a TRANSIENT or PERSISTENT DDS_DataWriter

DDS_DurabilityQosPolicy	writer_depth
	<<basic>> <<extension>> Indicates the number of samples per instance that a durable DDS_DataWriter will send to a late-joining DDS_DataReader.

DDS_DurabilityQosPolicy	storage_settings
	<<extension>> Configures durable writer history and durable reader state.

DDS_DurabilityServiceQosPolicy	service_cleanup_delay
	<<spec>> Controls when the service is able to remove all information regarding a data instances.

DDS_DurabilityServiceQosPolicy	max_samples
	<<spec>> Part of resource limits QoS policy to apply when feeding a late joiner.

DDS_DurabilityServiceQosPolicy	max_instances
	<<spec>> Part of resource limits QoS policy to apply when feeding a late joiner.

DDS_DurabilityServiceQosPolicy	max_samples_per_instance
	<<spec>> Part of resource limits QoS policy to apply when feeding a late joiner.

DDS_PresentationQosPolicy	access_scope
	<<spec>> Determines the largest scope spanning the entities for which the order and coherency of changes can be preserved.

DDS_PresentationQosPolicy	coherent_access
	<<spec>> Specifies support for coherent access. Controls whether coherent access is supported within the scope `access_scope`.

DDS_PresentationQosPolicy	ordered_access
	<<spec>> Specifies support for ordered access to the samples received at the subscription end. Controls whether ordered access is supported within the scope `access_scope`.

DDS_PresentationQosPolicy	drop_incomplete_coherent_set
	<<extension>> Indicates whether or not a DDS_DataReader should drop samples from an incomplete coherent set (one for which not all the samples were received). Such samples are reported as lost in the SAMPLE_LOST Status.

DDS_DeadlineQosPolicy	period
	<<basic>> <<spec>> Duration of the deadline period.

DDS_LatencyBudgetQosPolicy	duration
	<<spec>> Duration of the maximum acceptable delay.

DDS_OwnershipQosPolicy	kind
	<<basic>> <<spec>> The kind of ownership

DDS_OwnershipStrengthQosPolicy	value
	<<basic>> <<spec>> The strength value used to arbitrate among multiple writers.

DDS_TimeBasedFilterQosPolicy	minimum_separation
	<<basic>> <<spec>> The minimum separation duration between subsequent samples.

DDS_HistoryQosPolicy	kind
	<<basic>> <<spec>> Specifies the kind of history to be kept.

DDS_HistoryQosPolicy	depth
	<<basic>> <<spec>> Specifies the number of samples per instance to be kept, when the `kind` is DDS_KEEP_LAST_HISTORY_QOS

DDS_ResourceLimitsQosPolicy	max_samples
	<<basic>> <<spec>> Represents the maximum samples the middleware can store for any one DDS_DataWriter (or DDS_DataReader).

DDS_ResourceLimitsQosPolicy	max_instances
	<<basic>> <<spec>> Represents the maximum number of instances a DDS_DataWriter (or DDS_DataReader) can manage.

DDS_ResourceLimitsQosPolicy	max_samples_per_instance
	<<spec>> Represents the maximum number of samples of any one instance a DDS_DataWriter (or DDS_DataReader) can manage.

DDS_LifespanQosPolicy	duration
	<<basic>> <<spec>> Maximum duration for the data's validity.

DDS_ReaderDataLifecycleQosPolicy	autopurge_nowriter_samples_delay
	<<spec>> Minimum duration for which the DDS_DataReader will maintain information regarding an instance once its `instance_state` becomes DDS_NOT_ALIVE_NO_WRITERS_INSTANCE_STATE.

DDS_ReaderDataLifecycleQosPolicy	autopurge_disposed_samples_delay
	<<spec>> Minimum duration for which the DDS_DataReader will maintain samples for an instance once its `instance_state` becomes DDS_NOT_ALIVE_DISPOSED_INSTANCE_STATE.

DDS_ReaderDataLifecycleQosPolicy	autopurge_disposed_instances_delay
	<<extension>> Minimum duration for which the DDS_DataReader will maintain information about a received instance once its `instance_state` becomes DDS_NOT_ALIVE_DISPOSED_INSTANCE_STATE and there are no samples for the instance in the DataReader queue.

DDS_ReaderDataLifecycleQosPolicy	autopurge_nowriter_instances_delay
	<<extension>> Minimum duration for which the DDS_DataReader will maintain information about a received instance once its `instance_state` becomes DDS_NOT_ALIVE_NO_WRITERS_INSTANCE_STATE and there are no samples for the instance in the DataReader queue.

DDS_TransportMulticastMappingQosPolicy	value
	<<extension>> A sequence of multicast communication mappings.

DDS_TransportMulticastQosPolicy	kind
	<<extension>> A value that specifies a way to determine how to obtain the multicast address.

DDS_DataWriterProtocolQosPolicy	virtual_guid
	<<extension>> The virtual GUID (Global Unique Identifier).

DDS_DataWriterProtocolQosPolicy	push_on_write
	<<extension>> Whether to push sample out when write is called.

DDS_BuiltinTopicReaderResourceLimits_t	initial_outstanding_reads
	<<extension>> The initial number of outstanding reads that have not called finish yet on the same built-in topic DDS_DataReader.

DDS_BuiltinTopicReaderResourceLimits_t	max_outstanding_reads
	<<extension>> The maximum number of outstanding reads that have not called finish yet on the same built-in topic DDS_DataReader.

DDS_BuiltinTopicReaderResourceLimits_t	max_samples_per_read
	<<extension>> Maximum number of samples that can be read/taken on a same built-in topic DDS_DataReader.

DDS_BatchQosPolicy	source_timestamp_resolution
	<<extension>> Batch source timestamp resolution.

DDS_MonitoringEventDistributionSettings	publication_period
	<<basic>> <<extension>> Period at which the event metric thread publishes the event metrics that have changed since the last time they were published.

DDS_MonitoringPeriodicDistributionSettings	polling_period
	<<basic>> <<extension>> Period at which the periodic metric thread polls and publishes the periodic metrics.

DDS_MonitoringLoggingDistributionSettings	publication_period
	<<basic>> <<extension>> Period at which the logging thread publishes log messages.

DDS_ChannelSettings_t	priority
	<<extension>> Publication priority

DDS_MultiChannelQosPolicy	channels
	<<extension>> A sequence of DDS_ChannelSettings_t used to configure the channels' properties. If the length of the sequence is zero, the QoS policy will be ignored.

DDS_MultiChannelQosPolicy	filter_name
	<<extension>> Name of the filter class used to describe the filter expressions of a MultiChannel DataWriter.