- u -

• unicast_locators : DDS::PublicationBuiltinTopicData , DDS::SubscriptionBuiltinTopicData
• UNKNOWN_SAMPLE_IDENTITY : DDS::SampleIdentity_t
• UNKNOWN_SERVICE_ID : DDS::ServiceRequest
• use_shared_exclusive_area : DDS::ExclusiveAreaQosPolicy
• user_data : DDS::ParticipantBuiltinTopicData , DDS::PublicationBuiltinTopicData , DDS::SubscriptionBuiltinTopicData