RTI Connext DDS Micro C API  Version 3.0.1
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View States

DDS_ViewStateKind and associated elements More...

Typedefs

typedef DDS_UnsignedLong DDS_ViewStateMask
 A bit-mask (list) of view states, i.e. DDS_ViewStateKind.

Enumerations

enum  DDS_ViewStateKind { DDS_NEW_VIEW_STATE = 0x0001 << 0, DDS_NOT_NEW_VIEW_STATE = 0x0001 << 1 }
 Indicates whether or not an instance is new. More...

Variables

const DDS_ViewStateMask DDS_ANY_VIEW_STATE
 Any view state DDS_NEW_VIEW_STATE | DDS_NOT_NEW_VIEW_STATE.

Detailed Description

DDS_ViewStateKind and associated elements


Typedef Documentation

A bit-mask (list) of view states, i.e. DDS_ViewStateKind.


Enumeration Type Documentation

Indicates whether or not an instance is new.

For each instance (identified by the key), the middleware internally maintains a view state relative to each DDS_DataReader. The view state can be either:

  • DDS_NEW_VIEW_STATE indicates that either this is the first time that the DDS_DataReader has ever accessed samples of that instance, or else that the DDS_DataReader has accessed previous samples of the instance, but the instance has since been reborn (i.e. become not-alive and then alive again).

The view_state available in the DDS_SampleInfo is a snapshot of the view state of the instance relative to the DDS_DataReader used to access the samples at the time the collection was obtained (i.e. at the time read or take was called). The view_state is therefore the same for all samples in the returned collection that refer to the same instance.

Once an instance has been detected as not having any "live" writers and all the samples associated with the instance are "taken" from the DDS_DataReader, the middleware can reclaim all local resources regarding the instance. Future samples will be treated as "never seen."

Enumerator:
DDS_NEW_VIEW_STATE 

New instance. This latest generation of the instance has not previously been accessed.

DDS_NOT_NEW_VIEW_STATE 

Not a new instance. This latest generation of the instance has previously been accessed.


Variable Documentation

const DDS_ViewStateMask DDS_ANY_VIEW_STATE

RTI Connext DDS Micro C API Version 3.0.1 Copyright © Thu Oct 24 2019 Real-Time Innovations, Inc