Std.Ip.Address

type

An internet address.

Both families are held in one 128-bit number so that every operation is written once; an IPv4 address uses the low 32 bits. The family is part of the value, so 0.0.0.1 and ::1 are different addresses even though the number is the same — which is also why an IPv4-mapped IPv6 address is not equal to the IPv4 address it carries until unmap says it is.