Create Domain with specific Qos File

Hello Potoman,

The DomainParticipantFactory is a singleton class, so every time you set and get its QoS you are operating over the same object. As a result, when you call factory->set_qos(factory_qos) you are actually overwriting the value of the different url_profile sequence with your new QoS file. To add a new file instead of overwriting the value of whatever was in there, you will need to add new elements to the sequence every time you want to add a new XML file with new QoS definitions.

This is more or less what I would in your createParticipant() function to be able to load more than one QoS file:

void DomainParticipantManager::createParticipant(int domainId, const CString & qosFile)
{
    DDSDomainParticipantFactory * factory = NULL;    
    DDS_DomainParticipantFactoryQos factory_qos;

    /* Get DDSDomainParticipantFactory instance */
    factory = DDSDomainParticipantFactory::get_instance();
    if (factory == NULL) {
        //report error accordingly
    }

    /* Get DDSParticipantFactory QoS */
    factory->get_qos(factory_qos);

    /* Get current length of url_profile sequence */
    DDS_Long url_profile_seq_len = factory_qos.profile.url_profile.length();

    /* Ensure new length of url_profile sequence, i.e., old length + 1 */
    if (!factory.qos.profile.url_profile.ensure_length(url_profile_seq_len + 1,
                                                       url_profile_seq_len + 1)) {
         DDS_DomainParticipantFactoryQos_finalize(&factory_qos);
         //report error accordingly
    }
    /* Add QoS file to the sequence. It will be the last element */
    factory_qos.profile.url_profile[url_profile_seq_length] = 
        DDS_String_dup(qosFile);
    ...
    
    DDS_DomainParticipantFactoryQos_finalize(&factory_qos);

}

Now if you want to create DomainParticipants with different QoS profiles you will need to create in your XML files different QoS profiles in different QoS libraries that you will need to specify when creating your participant. To specify an specific QoS profile when you create the participant you will need to call the DDSDomainParticipantFactory::create_participant_with_profile() method. I would change your function to pass the name of the library and QoS profile.

void DomainParticipantManager::createParticipant(int domainId, const CString & qosFile, 
    const char *library_name, *profile_name)
{
    /* before you would have logic we added in the previous snippet */ 
    
    /* Create participant with profile */
    DDSDomainParticipant *participant = NULL;
    participant = factory->create_participant_with_profile(domainId,
                                                           library_name,
                                                           profile_name,
                                                           NULL /*listener*/,
                                                           DDS_STATUS_MASK_NONE);
    if (participant == NULL) {
         // Report error accordingly
    }   
     
}  

Let me know if this works for you.

Best regards,
Fernando.

Hello Potoman,

When you create a DomainParticipant you are creating an entity that will interact with other DomainParticipants within the same domain. You can have many different DomainParticipants within the same domain with different QoS profiles. Each of these DomainParticipants needs to be created with an specific QoS profiles. If its profile is not specified (i.e., if you pass the PARTICIPANT_QOS_DEFAULT), the middleware will decide what is the default QoS profile in your case.

I have some doubts of what you intent to create when you pass an XML file to the DomainParticipantFactory to create a DomainParticipant. In DDS, you have to specify the QoS profile you want to create your participant with. XML files you may load are just containers where these QoS profiles are stored. In other words, all your profiles (i.e., a, b, c, d, and e) could be in the same XML file--it will not make a different in the end. 

Once you have written all the QoS profiles that you want your different participants to use, you need to load them. To load them you need to add them to a sequence of files to be loaded, which is contained in the DomainParticipantFactoryQoS (i.e., factory_qos.profile.url_profile). You will find how to do this in my previous answer. Once they are loaded and available, you need to explicitly specify the profile you want to create your participant with. DomainParticipants can only be created with one QoS profiles. If you want to use another QoS profile, you will need to create a different participant within the same domain. 

In summary, what you want to achieve is not possible. You can only create a DomainParticipant with a single QoS profile (regardless of whether is the default one or any of the other available ones). If you give us more detail about your use case, we will try to find a workaround to achieve what you want. 

Thanks,
Fernando.