I once added ipv6 capabilities to a very old windows software. It turned out that before Windows 8, there was no way to asynchronously resolve an AAAA record in

I once added ipv6 capabilities to a very old windows software. It turned out that before Windows 8, there was no way to asynchronously resolve an AAAA record in a single threaded app. For the good old A records, you could ask Windows to resolve a hostname and it would send you a window message when it was done. So after fighting with multithreading in this archane app - I forgot what exactly the problems were - I wrote a very simple resolver that would only be able to handle AAAA lookups. It really is surprisingly simple. I think the more involved part was googling how to retrieve the system's configured DNS servers. ;)