+/*
+ * Entrypoints for poll-loop based asynch io:
+ */
+
+struct pollfd;
+/* In case your system doesn't have it or you forgot to include
+ * <sys/poll.h>, to stop the following declarations from causing
+ * problems. If your system doesn't have poll then the following
+ * entrypoints will not be defined in libadns. Sorry !
+ */
+
+int adns_beforepoll(adns_state ads, struct pollfd *fds,
+ int *nfds_io, int *timeout_io,
+ const struct timeval *now);
+/* Finds out which fd's adns is interested in, and when it would like
+ * to be able to time things out. This is in a form suitable for use
+ * with poll(2).
+ *
+ * On entry, usually fds should point to at least *nfds_io structs.
+ * adns will fill up to that many structs will information for poll,
+ * and record in *nfds_io how many structs it filled. If it wants to
+ * listen for more structs then *nfds_io will be set to the number
+ * required and _beforepoll will return ERANGE.
+ *
+ * You may call _beforepoll with fds==0 and *nfds_io 0, in which case
+ * adns will fill in the number of fds that it might be interested in
+ * in *nfds_io, and always return either 0 (if it is not interested in
+ * any fds) or ERANGE (if it is).
+ *
+ * NOTE that (unless now is 0) adns may acquire additional fds
+ * from one call to the next, so you must put adns_beforepoll in a
+ * loop, rather than assuming that the second call (with the buffer
+ * size requested by the first) will not return ERANGE.
+ *
+ * adns only ever sets POLLIN, POLLOUT and POLLPRI in its pollfd
+ * structs, and only ever looks at those bits. POLLPRI is required to
+ * detect TCP Urgent Data (which should not be used by a DNS server)
+ * so that adns can know that the TCP stream is now useless.
+ *
+ * In any case, *timeout_io should be a timeout value as for poll(2),
+ * which adns will modify downwards as required. If the caller does
+ * not plan to block then *timeout_io should be 0 on entry, or
+ * alternatively, timeout_io may be 0. (Alternatively, the caller may
+ * use _beforeselect with timeout_io==0 to find out about file
+ * descriptors, and use _firsttimeout is used to find out when adns
+ * might want to time something out.)
+ *
+ * adns_beforepoll will return 0 on success, and will not fail for any
+ * reason other than the fds buffer being too small (ERANGE).
+ *
+ * This call will never actually do any I/O. If you supply the
+ * current time it will not change the fds that adns is using or the
+ * timeouts it wants.
+ *
+ * In any case this call won't block.
+ */
+
+#define ADNS_POLLFDS_RECOMMENDED 2
+/* If you allocate an fds buf with at least RECOMMENDED entries then
+ * you are unlikely to need to enlarge it. You are recommended to do
+ * so if it's convenient. However, you must be prepared for adns to
+ * require more space than this.
+ */
+
+void adns_afterpoll(adns_state ads, const struct pollfd *fds, int nfds,
+ const struct timeval *now);
+/* Gives adns flow-of-control for a bit; intended for use after
+ * poll(2). fds and nfds should be the results from poll(). pollfd
+ * structs mentioning fds not belonging to adns will be ignored.
+ */
+
+
+adns_status adns_rr_info(adns_rrtype type,
+ const char **rrtname_r, const char **fmtname_r,
+ int *len_r,
+ const void *datap, char **data_r);
+/*
+ * Get information about a query type, or convert reply data to a
+ * textual form. type must be specified, and the official name of the
+ * corresponding RR type will be returned in *rrtname_r, and
+ * information about the processing style in *fmtname_r. The length
+ * of the table entry in an answer for that type will be returned in
+ * in *len_r. Any or all of rrtname_r, fmtname_r and len_r may be 0.
+ * If fmtname_r is non-null then *fmtname_r may be null on return,
+ * indicating that no special processing is involved.
+ *
+ * data_r be must be non-null iff datap is. In this case *data_r will
+ * be set to point to a string pointing to a representation of the RR
+ * data in master file format. (The owner name, timeout, class and
+ * type will not be present - only the data part of the RR.) The
+ * memory will have been obtained from malloc() and must be freed by
+ * the caller.
+ *
+ * Usually this routine will succeed. Possible errors include:
+ * adns_s_nomemory
+ * adns_s_rrtypeunknown
+ * adns_s_invaliddata (*datap contained garbage)
+ * If an error occurs then no memory has been allocated,
+ * and *rrtname_r, *fmtname_r, *len_r and *data_r are undefined.
+ *
+ * There are some adns-invented data formats which are not official
+ * master file formats. These include:
+ *
+ * Mailboxes if __qtf_mail822: these are just included as-is.
+ *
+ * Addresses (adns_rr_addr): these may be of pretty much any type.
+ * The representation is in two parts: first, a word for the address
+ * family (ie, in AF_XXX, the XXX), and then one or more items for the
+ * address itself, depending on the format. For an IPv4 address the
+ * syntax is INET followed by the dotted quad (from inet_ntoa).
+ * Currently only IPv4 is supported.
+ *
+ * Text strings (as in adns_rr_txt) appear inside double quotes, and
+ * use \" and \\ to represent " and \, and \xHH to represent
+ * characters not in the range 32-126.
+ *
+ * Hostname with addresses (adns_rr_hostaddr): this consists of the
+ * hostname, as usual, followed by the adns_status value, as an
+ * abbreviation, and then a descriptive string (encoded as if it were
+ * a piece of text), for the address lookup, followed by zero or more
+ * addresses enclosed in ( and ). If the result was a temporary
+ * failure, then a single ? appears instead of the ( ). If the
+ * result was a permanent failure then an empty pair of parentheses
+ * appears (which a space in between). For example, one of the NS
+ * records for greenend.org.uk comes out like
+ * ns.chiark.greenend.org.uk ok "OK" ( INET 195.224.76.132 )
+ * an MX referring to a nonexistent host might come out like:
+ * 50 sun2.nsfnet-relay.ac.uk nxdomain "No such domain" ( )
+ * and if nameserver information is not available you might get:
+ * dns2.spong.dyn.ml.org timeout "DNS query timed out" ?
+ */
+
+const char *adns_strerror(adns_status st);
+const char *adns_errabbrev(adns_status st);
+const char *adns_errtypeabbrev(adns_status st);
+/* Like strerror but for adns_status values. adns_errabbrev returns
+ * the abbreviation of the error - eg, for adns_s_timeout it returns
+ * "timeout". adns_errtypeabbrev returns the abbreviation of the
+ * error class: ie, for values up to adns_s_max_XXX it will return the
+ * string XXX. You MUST NOT call these functions with status values
+ * not returned by the same adns library.
+ */
+
+#ifdef __cplusplus
+} /* end of extern "C" */
+#endif