Name not populated

[dmars1972]

I can't find any way to force a wait on a lescan for device name... I can get the addresses, but the name doesn't appear to be populated (yet), but I can't find any way to say 'go get the name' or 'wait for the name to show up' in get_advertisements. Meaning (using lescan example):

vector<AdvertisingResponse> ads = scanner.get_advertisements();

for(const auto& ad: ads) {
    cout << "Found device: " << ad.address << endl;

    if( ! ad.local_name)
        _**ad.getLocalName();**_  // added this as what I'm trying to accomplish
     cout << ad.local_name->name << endl;

Is there a way to do this I'm not seeing? The issue for me is I'm working on a whole group of devices, so I can't depend on filtering by MAC (hoping to just look at them by a name prefix).

[edrosten]

OK, three things. First, you need to make sure the scanner is set up as active, not passive. This is because most BLE devices don't advertise the name by default. Usually they just send out some basic information (a service, whether they're connectable, if they support active scanning). In active scanning mode, the BLE adapter asks the device for its name and it replies, so make sure it's in active mode (that's a constructor parameter but I believe it's the default).

Second, that means the name is basically never the first advertisement you receive. So, your loop needs to keep fetching advertisements until the one you want arrives. It needs to be something like this:

for(;;) {
    auto ads = scanner.get_advertisements();
    for(const auto& ad: ads) {
        if(ad.local_name) {
            do stuff here!
        }
    }
}

Thirdly, you might not need to use the name. There's probably some info embedded in the first packet that identifies the device, such as a service ID.

[dmars1972]

Thanks! The forever loop did it. I know precisely jack about bluetooth, so I've been using the name because at least I understand that. :)

[edrosten]

Glad to help. The name's a perfectly good way to do it.