11.4. DataReader profiles¶

The DataReader profiles allow declaring DataReaders from an XML file. These profiles are defined within the <data_reader> or <subscriber> XML tags. Thus, the following XML codes are equivalent.

DataReader profile - Definition method 1

DataReader profile - Definition method 2

<data_reader profile_name="my_datareader_profile">
    <topic>
        <!-- TOPIC_TYPE -->
    </topic>
    <qos>
        <!-- QOS -->
    </qos>
    <!-- Other elements -->
</data_reader>

<subscriber profile_name="my_subscriber_profile">
    <topic>
        <!-- TOPIC_TYPE -->
    </topic>
    <qos>
        <!-- QOS -->
    </qos>
    <!-- Other elements -->
</subscriber>

Important

The <data_reader> and <subscriber> XML tags are equivalent. Therefore, XML profiles in which the DataReaders are defined with the <subscriber> tag are fully compatible with Fast DDS.

11.4.1. DataReader XML attributes¶

The <data_reader> element has two attributes defined: profile_name and is_default_profile.

Name	Description	Use
`profile_name`	Sets the name under which the `<data_reader>` profile is registered in the DDS Domain, so that it can be loaded later by the DomainParticipant, as shown in Loading and applying profiles.	Mandatory
`is_default_profile`	Sets the `<data_reader>` profile as the default profile. Thus, if a default profile exists, it will be used when no other DataReader profile is specified at the DataReader’s creation.	Optional

11.4.2. DataReader configuration¶

The DataReader configuration is performed through the XML elements listed in the following table.

Name	Description	Values	Default
`<topic>`	TopicType configuration of the DataReader.	TopicType
`<qos>`	Subscriber QoS configuration.	QoS
`<times>`	It allows configuring some time related parameters of the DataReader.	Times
`<unicastLocatorList>`	List of input unicast locators. It expects a LocatorListType.	List of LocatorListType
`<multicastLocatorList>`	List of input multicast locators. It expects a LocatorListType.	List of LocatorListType
`<expectsInlineQos>`	It indicates if QoS is expected inline.	`bool`	`false`
`<historyMemoryPolicy>`	Memory allocation kind for DataReaders’s history.	MemoryManagementPolicy	`PREALLOCATED`
`<propertiesPolicy>`	Additional configuration properties.	PropertiesPolicyType
`<userDefinedID>`	Used for StaticEndpointDiscovery.	`int16_t`	-1
`<entityID>`	Set the `entity_id` of the RTPSEndpointQos class.	`int16_t`	-1
`<matchedPublishersAllocation>`	Sets the limits of the collection of matched DataWriters. See ParticipantResourceLimitsQos.	Allocation Configuration

Example

<?xml version="1.0" encoding="UTF-8" ?>
<dds>
    <profiles xmlns="http://www.eprosima.com/XMLSchemas/fastRTPS_Profiles" >
        <data_reader profile_name="sub_profile_name">
            <topic>
                <!-- TOPIC_TYPE -->
            </topic>

            <qos>
                <!-- QOS -->
            </qos>

            <times> <!-- readerTimesType -->
                <initialAcknackDelay>
                    <sec>0</sec>
                    <nanosec>70</nanosec>
                </initialAcknackDelay>

                <heartbeatResponseDelay>
                    <sec>0</sec>
                    <nanosec>5</nanosec>
                </heartbeatResponseDelay>
            </times>

            <unicastLocatorList>
                <!-- LOCATOR_LIST -->
                <locator>
                    <udpv4/>
                </locator>
            </unicastLocatorList>

            <multicastLocatorList>
                <!-- LOCATOR_LIST -->
                <locator>
                    <udpv4/>
                </locator>
            </multicastLocatorList>

            <expectsInlineQos>true</expectsInlineQos>

            <historyMemoryPolicy>DYNAMIC</historyMemoryPolicy>

            <propertiesPolicy>
                <!-- PROPERTIES_POLICY -->
            </propertiesPolicy>

            <userDefinedID>55</userDefinedID>

            <entityID>66</entityID>

            <matchedPublishersAllocation>
                <initial>0</initial>
                <maximum>0</maximum>
                <increment>1</increment>
            </matchedPublishersAllocation>
        </data_reader>
    </profiles>
<dds>

Note

LOCATOR_LIST means it expects a LocatorListType.
PROPERTIES_POLICY means that the label is a PropertiesPolicyType block.
For QOS details, please refer to QoS.
TOPIC_TYPE is detailed in section TopicType.

11.4.2.1. Times¶

Name	Description	Values	Default
`<initialAcknackDelay>`	Initial ACKNACK delay.	DurationType	70 ms
`<heartbeatResponseDelay>`	Response time delay when receiving a Heartbeat.	DurationType	5 ms