DDS_DataRepresentationQosPolicy Struct Reference

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

Data Fields
struct DDS_DataRepresentationIdSeq	value
	Sequence of representation identifiers.

Detailed Description

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

Entity:

DDS_Topic, DDS_DataReader, DDS_DataWriter

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

When representations are specified in the DDS_TopicQos, DDS_Publisher_copy_from_topic_qos copies the first element of the sequence, and DDS_Subscriber_copy_from_topic_qos copies the whole sequence.

Field Documentation

struct DDS_DataRepresentationIdSeq DDS_DataRepresentationQosPolicy::value

Sequence of representation identifiers.

[default] For DDS_Topic, DDS_DataWriter, and DDS_DataReader, 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.