4.3 Statuses

This section describes the different statuses that exist for an entity. A status represents a state or an event regarding the entity. For instance, maybe Connext DDS found a matching DataReader for a DataWriter, or new data has arrived for a DataReader.

Your application can retrieve an Entity’s status by:

• explicitly checking for any status changes with get_status_changes().
• explicitly checking a specific status with get_<status_name>_status().
• using a Listener, which provides asynchronous notification when a status changes.
• using StatusConditions and WaitSets, which provide a way to wait for status changes.

If you want your application to be notified of status changes asynchronously: create and install a Listener for the Entity. Then internal Connext DDS threads will call the listener methods when the status changes. See 4.4 Listeners.

If you want your application to wait for status changes: set up StatusConditions to indicate the statuses of interest, attach the StatusConditions to a WaitSet, and then call the WaitSet’s wait() operation. The call to wait() will block until statuses in the attached Conditions changes (or until a timeout period expires). See 4.6 Conditions and WaitSets.

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