OpenSplice C# API  v6.x
OpenSplice C# Data Distribution Service Data-Centric Publish-Subscribe API
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DDS.DestinationOrderQosPolicy Struct Reference

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Public Attributes

DestinationOrderQosPolicyKind Kind
 

Detailed Description

This QosPolicy controls the order in which the DataReader stores the data.

Attributes

Value Meaning Concerns RxO Changeable
A DestinationOrderQosPolicyKind:
kind 		controls the order in which the DataReader stores the data. This can be BY_RECEPTION_TIMESTAMP or BY_SOURCE_TIMESTAMP. Topic, DataReader, DataWriter Yes No
BY_RECEPTION_TIMESTAMP Indicates that data is ordered based on the reception time at each Subscriber. Since each subscriber may receive the data at different times there is no guaranteed that the changes will be seen in the same order. Consequently, it is possible for each subscriber to end up with a different final value for the data.
BY_SOURCE_TIMESTAMP Indicates that data is ordered based on a timestamp placed at the source (by the Service or by the application). In any case this guarantees a consistent final value for the data in all subscribers.

This policy controls how each subscriber resolves the final value of a data instance that is written by multiple DataWriter objects (which may be associated with different Publisher objects) running on different nodes.

The setting BY_RECEPTION_TIMESTAMP indicates that, assuming the OWNERSHIP policy allows it, the latest received value for the instance should be the one whose value is kept. This is the default value.

The setting BY_SOURCE_TIMESTAMP indicates that, assuming the OWNERSHIP policy allows it, a timestamp placed at the source should be used. This is the only setting that, in the case of concurrent same-strength DataWriter objects updating the same instance, ensures all subscribers will end up with the same final value for the instance. The mechanism to set the source timestamp is middleware dependent.

The value offered is considered compatible with the value requested if and only if the inequality “offered kind >= requested kind” evaluates to ‘TRUE.’ For the purposes of this inequality, the values of DESTINATION_ORDER kind are considered ordered such that BY_RECEPTION_TIMESTAMP < BY_SOURCE_TIMESTAMP.

This QoS plays a role within the scope of Eventual Consistency

Definition at line 1364 of file DdsDcpsStructs.cs.

Member Data Documentation

◆ Kind

DestinationOrderQosPolicyKind DDS.DestinationOrderQosPolicy.Kind

Definition at line 1366 of file DdsDcpsStructs.cs.

The documentation for this struct was generated from the following file: