old-README

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* Known Limitations (WARNING: some of these may be out of date)

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) An instance key must be a base type (not a complex type like array or
  struct).

  This limitation exists because the generated lessThan operator does
  not currently handle complex types.

  This limitation can be worked around by specifying multiple keys such
  that all of the base types in the complex type are specified.

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) Users must ensure that TopicDescriptions are not used after the
  associated Topic is deleted.

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) create_datawriter() does not wait for full association establishment;
  a write shortly after creating the datawriter may be dropped on
  the publisher side because add_associations() has not yet completed.

  The sample may also be dropped on the subscriber side even though
  the connection exists between the publisher and subscriber when
  the associations have not yet been mapped.

  If the publisher expects existing DataReaders to receive the
  messages it sends after creating the DataWriter, it must wait for
  full association before writing messages.

  You may perform the following to avoid message loss during association
  for an expected quantity of associated DataReaders:

    DDS::StatusCondition_var cond = writer->get_statuscondition();
    cond->set_enabled_statuses(DDS::PUBLICATION_MATCHED_STATUS);

    DDS::WaitSet_var ws = new DDS::WaitSet;
    ws->attach_condition(cond);

    DDS::Duration_t timeout =
      { DDS::DURATION_INFINITE_SEC, DDS::DURATION_INFINITE_NSEC };

    DDS::ConditionSeq conditions;
    DDS::PublicationMatchedStatus matches = { 0, 0, 0, 0, 0 };

    do {
      if (ws->wait(conditions, timeout) != DDS::RETCODE_OK) {
        // failure
      }

      if (writer->get_publication_matched_status(matches) !=
          DDS::RETCODE_OK) {
        // failure
      }

    } while (matches.current_count < 1);

    ws->detach_condition(cond);


  Note: DDS by its nature is not connection oriented.  That is, publication
        and subscription lifecycles are decoupled.  A number of QoS policies
        exist which help manage late joining readers and writers
        (i.e. DURABILITY).  For more information, please review the various
        QoS policies documented in the OpenDDS Developer's Guide.

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) Samples are only rejected for having more than
  qos.resource_limits.max_samples_per_instance NOT_READ samples in an
  instance.

  The implementation should also reject for too many total NOT_READ
  samples or too many instances.

  Since the OpenDDS implementation does not have hard limits with
  respect to these values this limitation is considered acceptable.

  Note: When more than resource_limits.max_samples are queued
  in the DataReader the heap will be used instead of pre-allocated
  memory.

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) The DURABILITY_SERVICE service_cleanup_delay support is currently
  experimental.  The corresponding DURABILITY service_cleanup_delay
  support is not available.

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) There is unspecified behavior when a non-volatile DataWriter persists
  samples belonging to an outstanding coherent change group.  The coherent
  samples are not persisted, however their presence may prematurely evict
  valid data samples from the durability cache due to resource limits.

  Coherent change groups are not maintained when their constituent data
  is persisted.  When a non-volatile DataWriter comes online, samples
  previously sent as a part of a change group will no longer maintain
  their atomicity.

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) The multicast transport design documentation maintains its own set of
  known issues; see: $DDS_ROOT/docs/html/multicast/multicast.html.