I’ve been looking on ipv6 lately, and even though I got a global /64 for free from he.net, I’m not that amused about ipv6 yet.
ipv6 link-local scope : if you have multiple interfaces with ipv6 link-local addresses, the operating system does not know which interface to use, so you have to append the interface to the hostname/ip when connecting hosts in link-local scope. If you do not use getaddrinfo, this information has to be passed to the bind/connect using