The socket API is governed by IETF RFCs and should be the same on all platforms including windows WRT IPv6.
For IPv4/IPv6 applications its ALL about getaddrinfo() and getnameinfo(). getaddrinfo is a genious - looks at DNS, port names and capabilities of the client to resolve the eternal question of can I use IPv4, IPv6 or both to reach a particular destination? Or if your going dualstack route and want it to return IPv4 mapped IPv6 addresses it will do that too.
It provides direct sockaddr * structure that can be plugged into bind(), recvfrom(), sendto() and address family for socket()... In many cases this means no messy sockaddr_in(6) structures to fill out and deal with.
For UDP implementations I would be careful about setting dual stack sockets or more generally binding to all interfaces (INADDR_ANY) The classic issue is that when addresses are not locked down (see bind()) to specific interfaces and the system has multiple interfaces requests responses may transit from different addresses for computers with multiple addresses based on the whims of the OS routing table confusing application protocols especially any systems with authentication requirements.
For UDP implementations where this is not a problem or TCP ... dual stack sockets can save a lot of time when IPv* enabling your system. One must be careful to not rely entirely on dual stack where its not absolutely necessary as there are no shortage of reasonable platforms (Old linux,BSD,Windows 2003) deployed with IPv6 stacks not capable of dual stack sockets.