X-Git-Url: https://git.distorted.org.uk/~mdw/adns/blobdiff_plain/620c146da30a20c2d9a6c572fdd0540558039d0e..d13d6381a4d0d09b7e2ab05a2c7c470f2de3c9fd:/src/adns.h

diff --git a/src/adns.h b/src/adns.h
index ce92c8b..21bc524 100644
--- a/src/adns.h
+++ b/src/adns.h
@@ -24,6 +24,9 @@
 
 #ifndef ADNS_H_INCLUDED
 #define ADNS_H_INCLUDED
+#ifdef __cplusplus
+extern "C" { /* I really dislike this - iwj. */
+#endif
 
 #include <stdio.h>
 
@@ -305,18 +308,21 @@ void adns_finish(adns_state ads);
  */
 
 
-struct adns_query adns_forallqueries_begin(adns_state ads, void **context_r);
-struct adns_query adns_forallqueries_next(adns_state ads, adns_query, void **context_r);
+void adns_forallqueries_begin(adns_state ads);
+adns_query adns_forallqueries_next(adns_state ads, void **context_r);
 /* Iterator functions, which you can use to loop over the outstanding
- * (submitted but not yet successfuly checked/waited) queries.  Each
- * function returns a query handle and a corresponding context pointer,
- * or returns 0 setting *context_r to 0 if there are no (more) queries.
- * There is no need to explicitly finish an iteration.  context_r may be 0.
+ * (submitted but not yet successfuly checked/waited) queries.
+ *
+ * You can only have one iteration going at once.  You may call _begin
+ * at any time; after that, an iteration will be in progress.  You may
+ * only call _next when an iteration is in progress - anything else
+ * may coredump.  The iteration remains in progress until _next
+ * returns 0, indicating that all the queries have been walked over,
+ * or ANY other adns function is called with the same adns_state (or a
+ * query in the same adns_state).  There is no need to explicitly
+ * finish an iteration.
  *
- * IMPORTANT: you MUST NOT call ANY other adns function with the same
- * adns_state, or with a query in the same adns_state, while you are
- * doing one of these iterations.  After such a call the iterator
- * value has undefined meaning and must not be used.
+ * context_r may be 0.  *context_r may not be set when _next returns 0.
  */
 
 /*
@@ -479,30 +485,35 @@ int adns_beforepoll(adns_state ads, struct pollfd *fds, int *nfds_io, int *timeo
  * listen for more structs then *nfds_io will be set to the number
  * required and _beforepoll will return ERANGE.
  *
- * NOTE that if 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.
- *
  * 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 0.
+ * in *nfds_io, and always return either 0 (if it is not interested in
+ * any fds) or ERANGE (if it is).
+ *
+ * NOTE that (unless timeout_io 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,
+ * 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.
+ * 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).
  *
- * If *now is not 0 then this call will never actually do any I/O, or
- * change the fds that adns is using or the timeouts it wants.  In any
- * case it won't block.
+ * This call will never actually do any I/O, or change the fds that
+ * adns is using or the timeouts it wants; and in any case it won't
+ * block.
  */
 
 #define ADNS_POLLFDS_RECOMMENDED 2
@@ -556,4 +567,7 @@ const char *adns_errabbrev(adns_status st);
  * not returned by the same adns library.
  */
 
+#ifdef __cplusplus
+} /* end of extern "C" */
+#endif
 #endif