DDS_LatencyBudgetQosPolicy Struct Reference

Provides a hint as to the maximum acceptable delay from the time the data is written to the time it is received by the subscribing applications. More...

#include <dds_c_infrastructure.h>

Data Fields
struct DDS_Duration_t	duration
	Duration of the maximum acceptable delay.

Detailed Description

Provides a hint as to the maximum acceptable delay from the time the data is written to the time it is received by the subscribing applications.

This policy is a hint to a DDS implementation; it can be used to change how it processes and sends data that has low latency requirements. The DDS specification does not mandate whether or how this policy is used.

Entity:

DDS_Topic, DDS_DataReader, DDS_DataWriter

Status:

DDS_OFFERED_INCOMPATIBLE_QOS_STATUS, DDS_REQUESTED_INCOMPATIBLE_QOS_STATUS

Properties:

RxO = YES
Changeable = YES

See also

DDS_PublishModeQosPolicy

DDS_FlowController

Usage

This policy provides a means for the application to indicate to the middleware the urgency of the data communication. By having a non-zero duration, RTI Connext DDS Micro can optimize its internal operation.

RTI Connext DDS Micro uses this policy only in conjunction with DDS_ASYNCHRONOUS_PUBLISH_MODE_QOS DDS_DataWriter instances associated with a DDS_EDF_FLOW_CONTROLLER_SCHED_POLICY DDS_FlowController. Together with the time of write, DDS_LatencyBudgetQosPolicy::duration determines the deadline of each individual sample. RTI Connext DDS Micro uses this information to prioritize the sending of asynchronously published data.

Compatibility

The value offered is considered compatible with the value requested if and only if the inequality offered duration <= requested duration evaluates to 'TRUE'.

Field Documentation

duration

struct DDS_Duration_t DDS_LatencyBudgetQosPolicy::duration

Duration of the maximum acceptable delay.

[default] 0 (meaning minimize the delay)