RTI Connext DDS Micro C API  Version 3.0.1
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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 it in conjunction with DDS_ASYNCHRONOUS_PUBLISH_MODE_QOS DDS_DataWriter instances associated with a DDS_EDF_FLOW_CONTROLLER_SCHED_POLICY DDS_FlowController only. 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

struct DDS_Duration_t DDS_LatencyBudgetQosPolicy::duration

Duration of the maximum acceptable delay.

[default] 0 (meaning minimize the delay)


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