RTI Connext DDS Micro
Version 2.4.6
|
Information that accompanies each sample that is read
or taken
.
More...
#include <dds_c_subscription.h>
Data Fields | |
DDS_SampleStateKind | sample_state |
The sample state of the sample. More... | |
DDS_ViewStateKind | view_state |
The view state of the instance. More... | |
DDS_InstanceStateKind | instance_state |
The instance state of the instance. More... | |
struct DDS_Time_t | source_timestamp |
The timestamp when the sample was written by a DataWriter. More... | |
DDS_InstanceHandle_t | instance_handle |
Identifies locally the corresponding instance. More... | |
DDS_InstanceHandle_t | publication_handle |
Identifies locally the DataWriter that modified the instance. More... | |
DDS_Boolean | valid_data |
Indicates whether the DataSample contains data or else it is only used to communicate a change in the instance_state of the instance. More... | |
struct DDS_Time_t | reception_timestamp |
<<eXtension>> The timestamp when the sample was committed by a DataReader. More... | |
Information that accompanies each sample that is read
or taken
.
The DDS_SampleInfo contains information pertaining to the associated Data
instance sample including:
sample_state
of the Data
value (i.e., if it has already been read or not) view_state
of the related instance (i.e., if the instance is new or not) instance_state
of the related instance (i.e., if the instance is alive or not) valid_data
flag. This flag indicates whether there is data associated with the sample. Some samples do not contain data indicating only a change on the instance_state
of the corresponding instance. source_timestamp
of the sample. This is the timestamp provided by the DDS_DataWriter at the time the sample was produced. DDS_SampleStateKind DDS_SampleInfo::sample_state |
The sample state of the sample.
Indicates whether or not the corresponding data sample has already been read.
DDS_ViewStateKind DDS_SampleInfo::view_state |
The view state of the instance.
Indicates whether the DDS_DataReader has already seen samples for the most-current generation of the related instance.
DDS_InstanceStateKind DDS_SampleInfo::instance_state |
The instance state of the instance.
Indicates whether the instance is currently in existence or, if it has been disposed, the reason why it was disposed.
struct DDS_Time_t DDS_SampleInfo::source_timestamp |
The timestamp when the sample was written by a DataWriter.
DDS_InstanceHandle_t DDS_SampleInfo::instance_handle |
Identifies locally the corresponding instance.
DDS_InstanceHandle_t DDS_SampleInfo::publication_handle |
Identifies locally the DataWriter that modified the instance.
The publication_handle
is the same DDS_InstanceHandle_t that is returned by the operation DDS_DataReader_get_matched_publications and can also be used as a parameter to the operation DDS_DataReader_get_matched_publication_data.
DDS_Boolean DDS_SampleInfo::valid_data |
Indicates whether the DataSample
contains data or else it is only used to communicate a change in the instance_state
of the instance.
Normally each DataSample
contains both a DDS_SampleInfo and some Data. However there are situations where a DataSample
contains only the DDS_SampleInfo and does not have any associated data. This occurs when the RTI Connext Micro notifies the application of a change of state for an instance that was caused by some internal mechanism (such as a timeout) for which there is no associated data. An example of this situation is when the RTI Connext Micro detects that an instance has no writers and changes the corresponding instance_state to DDS_NOT_ALIVE_NO_WRITERS_INSTANCE_STATE. The application can distinguish whether a particular DataSample
has data by examining the value of the valid_data
flag. If this flag is set to DDS_BOOLEAN_TRUE, then the DataSample
contains valid Data. If the flag is set to DDS_BOOLEAN_FALSE, the DataSample
contains no Data. To ensure correctness and portability, the valid_data
flag must be examined by the application prior to accessing the Data associated with the DataSample
and if the flag is set to DDS_BOOLEAN_FALSE, the application should not access the Data associated with the DataSample
, that is, the application should access only the DDS_SampleInfo.
struct DDS_Time_t DDS_SampleInfo::reception_timestamp |
<<eXtension>> The timestamp when the sample was committed by a DataReader.