10.6. Topic profiles¶

The topic profiles allow for configuring Topic from an XML file. These profiles are defined within the <topic> XML tags.

10.6.1. Topic XML attributes¶

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

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

10.6.2. Topic configuration¶

This XML element allows the configuration of the TopicQos.

Name	Description	Values
`<historyQos>`	It controls the behavior of Fast DDS when the value of an instance changes before it is finally communicated to some of its existing DataReaders.	HistoryQoS
`<resourceLimitsQos>`	It controls the resources that Fast DDS can use in order to meet the requirements imposed by the application and other QoS settings.	ResourceLimitsQos

Example

<topic profile_name="topic_example">
    <historyQos>
        <kind>KEEP_LAST</kind>
        <depth>20</depth>
    </historyQos>
    <resourceLimitsQos>
        <max_samples>5</max_samples>
        <max_instances>2</max_instances>
        <max_samples_per_instance>1</max_samples_per_instance>
        <allocated_samples>20</allocated_samples>
        <extra_samples>10</extra_samples>
    </resourceLimitsQos>
</topic>