RTI Connext C API  Version 5.3.1
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DDS_TypeConsistencyEnforcementQosPolicy Struct Reference

Defines the rules for determining whether the type used to publish a given topic is consistent with that used to subscribe to it. More...

Data Fields

DDS_TypeConsistencyKind kind
 Type consistency kind.
 

Detailed Description

Defines the rules for determining whether the type used to publish a given topic is consistent with that used to subscribe to it.

This policy defines a type consistency kind, which allows applications to select from among a set of predetermined behaviors. The following consistency kinds are specified: DDS_DISALLOW_TYPE_COERCION and DDS_ALLOW_TYPE_COERCION.

The type-consistency-enforcement rules consist of two steps:

Step 1. If both the DataWriter and DataReader specify a TypeObject, it is considered first. If the DataReader allows type coercion, then its type must be assignable from the DataWriter's type. If the DataReader does not allow type coercion, then its type must be structurally identical to the type of the DataWriter.

Step 2. If either the DataWriter or the DataReader does not provide a TypeObject definition, then the registered type names are examined. The DataReader's and DataWriter's registered type names must match exactly, as was true in RTI Connext releases prior to 5.0.0.

If either Step 1 or Step 2 fails, the Topics associated with the DataReader and DataWriter are considered to be inconsistent and the DDS_InconsistentTopicStatus is updated.

The default enforcement kind is DDS_ALLOW_TYPE_COERCION. However, when the middleware is introspecting the built-in topic data declaration of a remote DataReader in order to determine whether it can match with a local DataWriter, if it observes that no TypeConsistencyEnforcementQosPolicy value is provided (as would be the case when communicating with a Service implementation not in conformance with this specification), it assumes a kind of DDS_DISALLOW_TYPE_COERCION.

For additional information on type consistency enforcement refer to the Addendum for Extensible Types and the OMG Extensible and Dynamic Topic Types for DDS Specification.

Entity:
DDS_DataReader
Properties:
RxO = N/A
Changeable = UNTIL ENABLE

Field Documentation

DDS_TypeConsistencyKind DDS_TypeConsistencyEnforcementQosPolicy::kind

Type consistency kind.

[default] DDS_ALLOW_TYPE_COERCION


RTI Connext C API Version 5.3.1 Copyright © Mon Feb 19 2018 Real-Time Innovations, Inc