[cups] programmatically obtain connection

[Boncek, John]

Using CUPS 1.7.2 under Ubuntu 14.04 at http://localhost:631, the Printers page shows a list of available printers.  When you click one, it shows various information about that printer, including "Connection", with values like "socket:10.2..." or "usb://HP/..."  How can I programmatically get that information for a printer?  I've looked thru the CUPS API but can't see any way to do so.  I know how to get a list of destinations but that doesn't contain this information as far as I can see.  Thanks for any help you can provide.  (If this is the wrong list for a question like this, please point me to a better one.)