DDS_PropertyQosPolicy Struct Reference

Stores name/value(string) pairs that can be used to configure certain parameters of RTI Connext that are not exposed through formal QoS policies. Can also be used to store and propagate application-specific name/value pairs that can be retrieved by user code during discovery. More...

Data Fields
struct DDS_PropertySeq	value
	Sequence of properties. More...

Detailed Description

Stores name/value(string) pairs that can be used to configure certain parameters of RTI Connext that are not exposed through formal QoS policies. Can also be used to store and propagate application-specific name/value pairs that can be retrieved by user code during discovery.

Entity:

DDS_DomainParticipant DDS_DataReader DDS_DataWriter

Properties:

RxO = N/A;
Changeable = YES

See also

DDS_DomainParticipant_get_builtin_subscriber

Usage

The PROPERTY QoS policy can be used to associate a set of properties in the form of (name, value) pairs with a DDS_DataReader, DDS_DataWriter, or DDS_DomainParticipant. This is similar to the DDS_UserDataQosPolicy, except this policy uses (name, value) pairs, and you can select whether or not a particular pair should be propagated (included in the builtin topic).

This QoS policy may be used to configure:

• Durable Writer History, see Configuring Durable Writer History

• Durable Reader State, see Configuring Durable Reader State

• Builtin Transport Plugins, see UDPv4 Transport Property Names in Property QoS Policy of Domain Participant, UDPv6 Transport Property Names in Property QoS Policy of Domain Participant, and Shared Memory Transport Property Names in Property QoS Policy of Domain Participant

• Extension Transport Plugins, see Loading Transport Plugins through Property QoS Policy of Domain Participant

• Clock Selection

In addition, you may add your own name/value pairs to the Property QoS policy of an Entity. Via this QoS policy, you can direct RTI Connext to propagate these name/value pairs with the discovery information for the Entity. Applications that discover the Entity can then access the user-specific name/value pairs in the discovery information of the remote Entity. This allows you to add meta-information about an Entity for application-specific use, for example, authentication/authorization certificates (which can also be done using the DDS_UserDataQosPolicy or DDS_GroupDataQosPolicy).

Reasons for Using the PropertyQosPolicy

• Supports dynamic loading of extension transports

• Supports multiple instances of the builtin transports

• Allows full pluggable transport configuration for non-C/C++ language bindings (Java, .NET, etc.)

• Avoids the process of creating entities disabled, changing their QoS settings, then enabling them

• Allows selection of clock

Some of the RTI Connext capabilities configurable via the Property QoS policy can also be configured in code via APIs. However, the Property QoS policy allows you to configure those parameters via XML files. In addition, some of the configuration APIs will only work if the Entity was created in a disabled state and then enabled after the configuration change was applied. By configuring those parameters using the Property QoS policy during entity creation, you avoid the additional work of first creating a disabled entity and then enabling it afterwards.

There are helper functions to facilitate working with properties, see the PROPERTY page.

Field Documentation

value

struct DDS_PropertySeq DDS_PropertyQosPolicy::value

Sequence of properties.

[default] An empty list.