====== F.3 Group Data  ======
[[dido:public:ra:xapend:xapend.f_qos:start| Return to DDS Quality of Service ]]

The ''GROUP_DATA'' [[dido:public:ra:xapend:xapend.a_glossary:q:qos|QoS]] allows the [[dido:public:ra:xapend:xapend.a_glossary:a:application|application]] to attach additional information to the created ''[[dido:public:ra:xapend:xapend.a_glossary:p:publisher|Publisher]]'' or ''[[dido:public:ra:xapend:xapend.a_glossary:s:subscriber|Subscriber]]''. The value of the ''GROUP_DATA'' is available to the application on the ''DataReader'' and ''DataWrite''r entities and is propagated by means of the built-in topics. 

This QoS can be used by an application combination with the ''DataReaderListener'' and ''DataWriterListener'' to implement matching policies similar to those of the ''[[dido:public:ra:xapend:xapend.a_glossary:p:partition|PARTITION QoS]]'' except the decision can be made based on an application-defined [[dido:public:ra:xapend:xapend.a_glossary:p:policy|policy]].

Source: [[https://www.omg.org/spec/DDS/1.4/PDF | DDS 1.4 Spec]]