Why sockets::connect or sockets::bindOrDie always use sizeof sockaddr_in6 ?

[zhihuacc]

Hi guys, I don't understand why the functions like sockets::connect or sockets::bindOrDie always pass sizeof struct sockaddr_in6 to the corresponding socket functions. I think InetAddress may capsulate an ipv4 address, and need check if it's ipv4 or ipv6 at runtime ?

[zhihuacc]

One possible explanation is, I think, sockaddr_in6 is longer than sockaddr_in and the socket functions bind() or connect() use the field family at the beginning of the struct to decide which type of address it is, instead of using the argument len ?