Topic Use Cases
[Programming How-To's]

Working with topics. More...

Registering a user data type

• Set up participant

• Register user data type of type T under the name "My_Type"

     const char* type_name = "My_Type";
     DDS_ReturnCode_t retcode;
  
     retcode = FooTypeSupport::register_type(participant, type_name);
     if (retcode != DDS_RETCODE_OK) {
         // ... error 
     }
  

Setting up a topic

• Set up participant

• Ensure user data type is registered

• Create a DDSTopic under the name "my_topic"

    const char* topic_name = "my_topic";
    const char* type_type = "My_Type";   // user data type
    DDS_TopicQos topic_qos;
    DDS_ReturnCode_t retcode;
  
    // MyTopicListener is user defined and 
    // extends DDSTopicListener
    DDSTopicListener* topic_listener = new MyTopicListener(); // or = NULL
  
    retcode = participant->get_default_topic_qos(topic_qos);
  
    if (retcode != DDS_RETCODE_OK) {
        // ... error 
    }
  
    DDSTopic* topic = participant->create_topic(topic_name, type_name,
                                                topic_qos, topic_listener,
                                                DDS_STATUS_MASK_ALL);
    if (topic == NULL) {
        // ... error 
  
    };
  

Tearing down a topic

• Delete DDSTopic:

    DDS_ReturnCode_t retcode;
  
    retcode = participant->delete_topic(topic);
  
    if (retcode != DDS_RETCODE_OK) {
        // ... check for cause of failure
    }