Instance-Specific Waitset

Hi,

I have an application that is subscribing to data on a specific instance. Code to do this works fine, as per the RTI worked examples:

dds::sub::LoanedSamples<DataType> samples = reader.select().max_samples(1).instance(instance_handle).read();

for (const auto& sample : samples) {
    if (sample.info().valid()) {

        std::cout << "Subscribed to InstanceID: " << sample.data().InstanceID() << std::endl;
        DataType dataOut = sample.data();

    }
}

Prior to this read command, I want my subscriber to wait until new data arrives on that specific instance. From the RTI worked examples, the waitset command to do this is:

status_condition.enabled_statuses(dds::core::status::StatusMask::data_available());
dds::core::cond::WaitSet waitset;
waitset += status_condition;

and then waitset.wait() prior to the code above.

However, (and I could be wrong here as I'm fairly new to DDS), but this waitset condition will trigger if data from any instance is published on the topic. However, I want to write a waitset condition that only triggers if new data from a specific InstanceID arrives on the topic. I have multiple publishers all writing to the same topic, but with different InstanceIDs. Each publisher has a paired subscriber that's only interested in data from that specific InstanceID.

Hopefully that makes sense.

Please can someone point me to the relevant doc page or write a simple example that I can follow?

Thank you :-) !