what is the meaning of publisher in DDS layer?

[wddpfx]

In DDS layer, there is participant、topic、publisher、subscriber。Publisher is just a container of dataWriter，But participant is a container of all entity。And participant and dataWriter have a map to rtpsParticipant and rtpsWriter at rpts layer. So what the meaning of publisher or subscriber?

[JesusPoderoso]

Hi @wddpfx, thanks for using Fast DDS.
Leaving apart the RTPS layer, a Publisher is a factory of DataWriters. Each DataWriter can only publish on a single Topic, with its related data-type, so a Publisher can publish on different Topics at the same time. Also, Publisher QoS are applied to all their DataWriters.

It occurs the same in the Subscriber case (and DataReaders).

In the Participant case, the participant's configured transport and several QoS are used by all the Publishers and Subscribers contained in the Participant.

[wddpfx]

好的，收到了你的邮件，我会尽快查看。