http://www.posadis.org/projects/poslib.php
Poslib DNS library - Default branch

http://www.posadis.org/poslib?DokuWiki=2b00f9da090fb9d4ad3d6e98b9c2f61f

Poslib is the C++ library for applications using the Domain Name System
that is used by all Posadis tools, including the Posadis DNS server and the
Zoneedit and Dnsquery tools. It consists of a library for creating client
applications using DNS, and a server library for DNS servers.


FireDNS Library
http://firestuff.org/projects/firedns
FireDNS Library
---------------
(c) 2002 Ian Gulliver under the GNU Public License, Version 2.
See GPL for more details.

From libfiredns(3):

libfiredns is a library for handling asynchronous DNS
requests.  It provides a very simple interface for sending
requests and parsing reponses, as well as low-timeout
blocking functions.  libfiredns functions have much lower
timeouts than the stock functions and tend to be faster
because they send requests to all configured system
nameservers at the same time.

If you have questions or comments, you can reach me at
ian@penguinhosting.net.



skadns

 Skadns is Kind of an Asynchronous DNS client software.

    * Kind of: it's small. Really small. But it just works.
    * Asynchronous: all DNS operations are non-blocking.
    * DNS client software: it's a DNS client, what you may know as a "stub resolver". To perform full DNS resolution, you will still need a full resolver like dnscache.

 Similar work

     * ares is an asynchronous DNS resolver library with a nice interface
     * and more configuration options than skadns (and a very reasonable
     * size). Use it if you find that skadns lacks configurability (you
     * shouldn't need more than it provides, but well, you're the user).
     * Yet it doesn't hide the DNS internals as opaquely as skadns does,
     * giving you a bunch of fds to select() on instead of just one.
         * adns works fine, and is small for a GNU project. Impressive. But
	 * the interface is still too complex and much too generic - the
	 * usual problems with GNU software.

	 
ADNS; documentation scares - is it still active
simular aims - different ways