+ elements is unwieldy. Hence the accessors.
+
+ The _ADDR accessors return the address as the struct in_addr or
+ in6_addr. The _DATA accessor returns a pointer to the address data
+ -- pretty much the same as the above, but cast to void*. The
+ _SCOPE accessor returns the address's scope_id, and makes sense
+ only when IPv6 and HAVE_SOCKADDR_IN6_SCOPE_ID are both defined. */
+
+#define ADDRESS_IPV4_IN_ADDR(x) ((x)->u.ipv4.addr)
+/* Don't use &x->u.ipv4.addr.s_addr because it can be #defined to a
+ bitfield, which you can't take an address of. */
+#define ADDRESS_IPV4_DATA(x) ((void *)&(x)->u.ipv4.addr)