Enum rmw_qos_liveliness_policy_e
Defined in File types.h
Enum Documentation
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enum rmw_qos_liveliness_policy_e
QoS liveliness enumerations that describe a publisher’s reporting policy for its alive status. For a subscriber, these are its requirements for its topic’s publishers.
Values:
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enumerator RMW_QOS_POLICY_LIVELINESS_SYSTEM_DEFAULT
Implementation specific default.
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enumerator RMW_QOS_POLICY_LIVELINESS_AUTOMATIC
The signal that establishes a Topic is alive comes from the ROS rmw layer.
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enumerator RMW_DECLARE_DEPRECATED
Explicitly asserting node liveliness is required in this case. This option is deprecated, use RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC if your application requires to assert liveliness manually.
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enumerator RMW_QOS_POLICY_LIVELINESS_MANUAL_BY_TOPIC
The signal that establishes a Topic is alive is at the Topic level. Only publishing a message on the Topic or an explicit signal from the application to assert liveliness on the Topic will mark the Topic as being alive.
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enumerator RMW_QOS_POLICY_LIVELINESS_UNKNOWN
Liveliness policy has not yet been set.
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enumerator RMW_QOS_POLICY_LIVELINESS_BEST_AVAILABLE
Will match the majority of endpoints and use a manual by topic policy if possible.
A policy will be chosen at the time of creating a subscription or publisher. A manual by topic policy will by chosen if it matches with all discovered endpoints, otherwise an automatic policy will be chosen.
The QoS policy reported by functions like
rmw_subscription_get_actual_qos
orrmw_publisher_get_actual_qos
may be best available, automatic, or manual by topic.Services and clients are not supported and default to the liveliness value in
rmw_qos_profile_services_default
.The middleware is not expected to update the policy after creating a subscription or publisher, even if the chosen policy is incompatible with newly discovered endpoints. Therefore, this policy should be used with care since non-deterministic behavior can occur due to races with discovery.
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enumerator RMW_QOS_POLICY_LIVELINESS_SYSTEM_DEFAULT