DDS_DataRepresentationQosPolicy Struct Reference

This QoS policy contains a list of representation identifiers used by DDSDataWriter and DDSDataReader entities to negotiate which data representation to use. More...

Public Attributes
struct DDS_DataRepresentationIdSeq	value
	Sequence of representation identifiers.

Detailed Description

This QoS policy contains a list of representation identifiers used by DDSDataWriter and DDSDataReader entities to negotiate which data representation to use.

Entity:

DDSTopic, DDSDataReader, DDSDataWriter

Status:

DDS_OFFERED_INCOMPATIBLE_QOS_STATUS, DDS_REQUESTED_INCOMPATIBLE_QOS_STATUS

Properties:

RxO = YES
Changeable = UNTIL ENABLE

See Also

DATA_REPRESENTATION

This policy has request-offer semantics. A DDSDataWriter may only offer a single representation. Attempting to put multiple representations in a DDSDataWriter will result in DDS_RETCODE_INCONSISTENT_POLICY. A DDSDataWriter will use its offered policy to communicate with its matched DDSDataReader entities. A DDSDataReader requests one or more representations. If a DDSDataWriter offers a representation that is contained within the sequence of the DDSDataReader, the offer satisfies the request and the policies are compatible. Otherwise, they are incompatible.

When representations are specified in the DDS_TopicQos, DDSPublisher::copy_from_topic_qos copies the first element of the sequence, and DDSSubscriber::copy_from_topic_qos copies the whole sequence.

Member Data Documentation

struct DDS_DataRepresentationIdSeq DDS_DataRepresentationQosPolicy::value

Sequence of representation identifiers.

[default] For DDSTopic, DDSDataWriter, and DDSDataReader, a list with one element: DDS_AUTO_DATA_REPRESENTATION.

Note

An empty sequence is equivalent to a list with one element: DDS_XCDR_DATA_REPRESENTATION.