Nested Structure IDL

Hi Gerado,

Your explanation is great, i have a better understanding now. I had managed to write simple publishing and subscribing codes based on the sample.idl. It works perfectly. Thanks a lot.

Hi Gerado,

I got another question here:

I created nested structures in .IDL with 2 topic names Hums_PBit_Info_T & Hums_Parameter_Info_T

typedef string<500> String500_T;
typedef string<50> String50_T;

enum ResourceType_E {
	RESOURCE_TYPE__APPLICATION,
	RESOURCE_TYPE__BRAKE,
	RESOURCE_TYPE__CREWSTATION,
	RESOURCE_TYPE__ACOUSTIC,
	RESOURCE_TYPE__CAMERA
};

enum HumsHealthBIT_E {
	HUMS_HEALTH_BIT__GOOD,
	HUMS_HEALTH_BIT__SERVICE,
	HUMS_HEALTH_BIT__WARNING,
	HUMS_HEALTH_BIT__DEGRADED,
	HUMS_HEALTH_BIT__FAILED
};

typedef struct tag_VsiTime_T { 
	long long seconds; 
	unsigned long nanoseconds; 
}VsiTime_T;

typedef struct tag_IdentifierType_T { 
	long id; 
	ResourceType_E idType; 
}IdentifierType_T;

struct Hums_PBit_Info_T { 
	IdentifierType_T resourceId; 
	HumsHealthBIT_E result;
	String500_T extendedResult;
	VsiTime_T timeOfDataGeneration; 
};

struct Hums_Parameter_Info_T { 
	IdentifierType_T resourceId; 
	String50_T parameterId;
	double value;
	VsiTime_T timeOfDataGeneration; 
};
 

After writing publishing codes as below, my subscription software can receive the data. And from admin console, i can see the datatype of topic Hums_Parameter_Info_T.

However, if i change the code to use topic Hums_PBit_Info_T, my subscribing software is not receiving any data and at admin console i cannot see any datatype of topic Hums_PBit_Info_T.

I understand that i can have multiple writers in 1 publisher and multiple readers in 1 subscriber (which i already coded). Im just doing a quick code change and check as the prior is also not reading my Hums_PBit_Info_T too.

I had spent hours on it but cannot find what i did wrong.

Hi Gerado,

By the way, my publishing codes as follows:

public class Hums_Publisher
{

    public static void Main(string[] args)
    {

        // --- Get domain ID --- //
        int domain_id = 0;
        if (args.Length >= 1)
        {
            domain_id = Int32.Parse(args[0]);
        }

        // --- Get max loop count; 0 means infinite loop --- //
        int sample_count = 0;
        if (args.Length >= 2)
        {
            sample_count = Int32.Parse(args[1]);
        }

        // --- Run --- //
        try
        {
            Hums_Publisher.publish(
                domain_id, sample_count);
        }
        catch (DDS.Exception)
        {
            Console.WriteLine("error in publisher");
        }
    }

    static void publish(int domain_id, int sample_count)
    {

        // --- Create participant --- //

        DDS.DomainParticipant participant =
        DDS.DomainParticipantFactory.get_instance().create_participant(
            domain_id,
            DDS.DomainParticipantFactory.PARTICIPANT_QOS_DEFAULT,
            null /* listener */,
            DDS.StatusMask.STATUS_MASK_NONE);
        if (participant == null)
        {
            shutdown(participant);
            throw new ApplicationException("create_participant error");
        }

        // --- Create publisher --- //

        DDS.Publisher publisher = participant.create_publisher(
            DDS.DomainParticipant.PUBLISHER_QOS_DEFAULT,
            null /* listener */,
            DDS.StatusMask.STATUS_MASK_NONE);
        if (publisher == null)
        {
            shutdown(participant);
            throw new ApplicationException("create_publisher error");
        }

        // --- Create topic --- //

        /* Register type before creating topic */
        System.String type_name = Hums_Parameter_Info_TTypeSupport.get_type_name();
        try
        {
            Hums_Parameter_Info_TTypeSupport.register_type(
            participant, type_name);
        }
        catch (DDS.Exception e)
        {
            Console.WriteLine("register_type error {0}", e);
            shutdown(participant);
            throw e;
        }

        DDS.Topic topic = participant.create_topic(
            "Example Hums_Parameter_Info_T",
            type_name,
            DDS.DomainParticipant.TOPIC_QOS_DEFAULT,
            null /* listener */,
            DDS.StatusMask.STATUS_MASK_NONE);
        if (topic == null)
        {
            shutdown(participant);
            throw new ApplicationException("create_topic error");
        }

        // --- Create writer --- //

        DDS.DataWriter writer = publisher.create_datawriter(
            topic,
            DDS.Publisher.DATAWRITER_QOS_DEFAULT,
            null /* listener */,
            DDS.StatusMask.STATUS_MASK_NONE);
        if (writer == null)
        {
            shutdown(participant);
            throw new ApplicationException("create_datawriter error");
        }
        Hums_Parameter_Info_TDataWriter Hums_Parameter_Info_T_writer =
            (Hums_Parameter_Info_TDataWriter)writer;

        // --- Write --- //

        /* Create data sample for writing */
        Hums_Parameter_Info_T instance = Hums_Parameter_Info_TTypeSupport.create_data();
        if (instance == null)
        {
            shutdown(participant);
            throw new ApplicationException(
            "Hums_Parameter_Info_TTypeSupport.create_data error");
        }

        DDS.InstanceHandle_t instance_handle = DDS.InstanceHandle_t.HANDLE_NIL;

        /* Main loop */
        const System.Int32 send_period = 4000; // milliseconds
        for (int count = 0;
           (sample_count == 0) || (count < sample_count);
           ++count)
        {
            Console.WriteLine("Writing Hums_Parameter_Info_T, count {0}", count);

            /* My Data */
            instance.resourceId.id = 2;
            instance.resourceId.idType = ResourceType_E.RESOURCE_TYPE__BATTERY;
            //instance.result = HumsHealthBIT_E.HUMS_HEALTH_BIT__GOOD; 
            //instance.extendedResult = "Hello there";
            instance.parameterId = "Para_1";
            instance.value = 40;
            instance.timeOfDataGeneration.nanoseconds = 333;
            instance.timeOfDataGeneration.seconds = 12;
            //

            try
            {
                Hums_Parameter_Info_T_writer.write(instance, ref instance_handle);
            }
            catch (DDS.Exception e)
            {
                Console.WriteLine("write error {0}", e);
            }

            System.Threading.Thread.Sleep(send_period);
        }
    }
}

..........