Here is a list of all documented struct and union fields with links to the struct/union documentation for each field:

- u -

• unacknowledged_count : DDS_ReliableSampleUnacknowledgedStatus
• unicast_locator : DDS_PublicationBuiltinTopicData , DDS_SubscriptionBuiltinTopicData
• user_data : OSAPI_ThreadInfo , DDS_DataReaderQos , DDS_DataWriterQos , DDS_SubscriptionBuiltinTopicData , DDS_DomainParticipantQos , DDS_PublicationBuiltinTopicData , UDP_TransformRule , DDS_ParticipantBuiltinTopicData
• user_multicast_port_offset : DDS_RtpsWellKnownPorts_t
• user_traffic : DDS_DomainParticipantQos
• user_unicast_port_offset : DDS_RtpsWellKnownPorts_t