+ return sockaddrcmp(a->ai_addr, b->ai_addr);
+}
+
+/** @brief Comparison function for socket addresses
+ *
+ * Suitable for qsort().
+ */
+int sockaddrcmp(const struct sockaddr *a,
+ const struct sockaddr *b) {
+ const struct sockaddr_in *ina, *inb;
+ const struct sockaddr_in6 *in6a, *in6b;
+
+ if(a->sa_family != b->sa_family) return a->sa_family - b->sa_family;
+ switch(a->sa_family) {