+ * Extra errors are possible from text2addr if addr specifies a scope
+ * name suffix (ie, it has a "%") and the scope suffix is not numeric:
+ * ENOSYS address is not link local
+ * ENXIO if_nametoindex said it wasn't a valid name
+ * EIO if_nametoindex went crazy (adns prints a message to stderr)
+ * Extra errors are possible from text2addr and addr2text with scopes:
+ * any other if_nametoindex failed