HISTORY
[QoS Policies]

Specifies the behavior of RTI Data Distribution Service in the case where the value of an instance changes (one or more times) before it can be successfully communicated to one or more existing subscribers. More...

Classes
struct	DDS_HistoryQosPolicy
	Specifies the behavior of RTI Data Distribution Service in the case where the value of a sample changes (one or more times) before it can be successfully communicated to one or more existing subscribers. More...
Enumerations
enum	DDS_HistoryQosPolicyKind {   DDS_KEEP_LAST_HISTORY_QOS,   DDS_KEEP_ALL_HISTORY_QOS }
	Kinds of history. More...
enum	DDS_RefilterQosPolicyKind {   DDS_NONE_REFILTER_QOS,   DDS_ALL_REFILTER_QOS,   DDS_ON_DEMAND_REFILTER_QOS }
	<<eXtension>> Kinds of Refiltering More...
Variables
const char *const	DDS_HISTORY_QOS_POLICY_NAME
	Stringified human-readable name for DDS_HistoryQosPolicy.

---

Detailed Description

Specifies the behavior of RTI Data Distribution Service in the case where the value of an instance changes (one or more times) before it can be successfully communicated to one or more existing subscribers.

---

Enumeration Type Documentation

enum DDS_HistoryQosPolicyKind

Kinds of history.

QoS:

DDS_HistoryQosPolicy

Enumerator:

DDS_KEEP_LAST_HISTORY_QOS

[default] Keep the last depth samples. On the publishing side, RTI Data Distribution Service will only attempt to keep the most recent depth samples of each instance of data (identified by its key) managed by the DDSDataWriter. On the subscribing side, the DDSDataReader will only attempt to keep the most recent depth samples received for each instance (identified by its key) until the application takes them via the DDSDataReader 's take() operation.

DDS_KEEP_ALL_HISTORY_QOS

Keep all the samples. On the publishing side, RTI Data Distribution Service will attempt to keep all samples (representing each value written) of each instance of data (identified by its key) managed by the DDSDataWriter until they can be delivered to all subscribers. On the subscribing side, RTI Data Distribution Service will attempt to keep all samples of each instance of data (identified by its key) managed by the DDSDataReader. These samples are kept until the application takes them from RTI Data Distribution Service via the take() operation.

enum DDS_RefilterQosPolicyKind

<<eXtension>> Kinds of Refiltering

QoS:

DDS_HistoryQosPolicy

Enumerator:

DDS_NONE_REFILTER_QOS	[default] Do not filter existing samples for a new reader On the publishing side, when a new reader matches a writer, the writer can be configured to filter previously written samples stored in the writer queue for the new reader. This option configures the writer to not filter any existing samples for the reader and the reader will do the filtering.
DDS_ALL_REFILTER_QOS	Filter all existing samples for a new reader. On the publishing side, when a new reader matches a writer, the writer can be configured to filter previously written samples stored in the writer queue. This option configures the writer to filter all existing samples for the reader when a new reader is matched to the writer.
DDS_ON_DEMAND_REFILTER_QOS	Filter existing samples only when they are requested by the reader. On the publishing side, when a new reader matches a writer, the writer can be configured to filter previously written samples stored in the writer queue. This option configures the writer to filter only existing samples that are requested by the reader.

---

Variable Documentation

const char* const DDS_HISTORY_QOS_POLICY_NAME

Stringified human-readable name for DDS_HistoryQosPolicy.