DDS_LivelinessChangedStatus Struct Reference
[DataReaders]

DDS_LIVELINESS_CHANGED_STATUS More...

List of all members.

Public Attributes
DDS_Long	alive_count
	The total count of currently alive DDSDataWriter entities that write the DDSTopic the DDSDataReader reads.
DDS_Long	not_alive_count
	The total count of currently not_alive DDSDataWriter entities that write the DDSTopic the DDSDataReader reads.
DDS_Long	alive_count_change
	The change in the alive_count since the last time the listener was called or the status was read.
DDS_Long	not_alive_count_change
	The change in the not_alive_count since the last time the listener was called or the status was read.
DDS_InstanceHandle_t	last_publication_handle
	An instance handle to the last remote writer to change its liveliness.

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Detailed Description

DDS_LIVELINESS_CHANGED_STATUS

The DDSDataReaderListener::on_liveliness_changed callback may be invoked for the following reasons:

• Liveliness is truly lost - a sample has not been received within the timeframe specified in DDS_LivelinessQosPolicy::lease_duration

• Liveliness is recovered after being lost.

• A new matching entity has been discovered.

• A QoS has changed such that a pair of matching entities are no longer matching (such as a change to the DDS_PartitionQosPolicy). In this case, RTI Data Distribution Service will no longer keep track of the entities' liveliness. Furthermore:
  • If liveliness was maintained: DDS_LivelinessChangedStatus::alive_count will decrease and DDS_LivelinessChangedStatus::not_alive_count will remain the same.
  • If liveliness had been lost: DDS_LivelinessChangedStatus::alive_count will remain the same and DDS_LivelinessChangedStatus::not_alive_count will decrease.

Examples:

HelloWorld_subscriber.cxx.

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Member Data Documentation

DDS_Long DDS_LivelinessChangedStatus::alive_count

The total count of currently alive DDSDataWriter entities that write the DDSTopic the DDSDataReader reads.

DDS_Long DDS_LivelinessChangedStatus::not_alive_count

The total count of currently not_alive DDSDataWriter entities that write the DDSTopic the DDSDataReader reads.

DDS_Long DDS_LivelinessChangedStatus::alive_count_change

The change in the alive_count since the last time the listener was called or the status was read.

DDS_Long DDS_LivelinessChangedStatus::not_alive_count_change

The change in the not_alive_count since the last time the listener was called or the status was read.

DDS_InstanceHandle_t DDS_LivelinessChangedStatus::last_publication_handle

An instance handle to the last remote writer to change its liveliness.