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Re: asynch name resolves

From: <>
Date: Wed, 23 Jul 2003 08:36:12 -0400

On Sun, Jul 20, 2003 at 01:01:58AM +0200, Daniel Stenberg wrote:
> On Wed, 16 Jul 2003 wrote:
> > Have you looked at "ares"?
> Nope, I have not.
> > The license is MIT which I believe makes it compatible with Curl.
> It would indeed. We could even incorporate it into our source tree, should we
> consider that a good thing.

It would also be interesting to see if the original author would like to be
involved in Curl...

> > The second is that it is UNIX based. In the last couple of days, we ported
> > it to windows and the example programs are working (but we haven't tested it
> > all that extensively yet).
> Ah, cool. Then I guess the only problem is the lack of IPv6 support, and we
> can surely survive not having that in a first step towards true and proper
> asynch resolves!
> I bet that we have a different problem as well, that you didn't mention here.
> This library probably only looks up names from DNS, but gethostbyname() and
> similar calls in the operating systems use more mechanisms than just DNS to
> find names and we need to support those as well... And that might take some
> platform dependent stuff. Or does ares take this into account already?

Ares seems to support the gethostbyname interface. I believe it uses
/etc/resolv.conf to find name servers (and implements the proper search)
and it uses /etc/hosts for local names. The windows port should be
doing roughly the equivalent steps by getting the name server information
out of the registry and using the c:\windows\system\hosts (or whatever it's
called file).

> > If Curl is interested in looking into this library, I'd be glad to make a
> > patch available as well as a VC++ project for the windows version of the
> > library.
> I think this sounds and seems highly interesting. I'll be back for real from
> my vacation this upcoming week and I hope to be able to get some time to dig
> into ares a bit deeper then.
> I'll appreciate all help, patches and things you can provide!

I've put two files up on our web server:

The first file is a patch against the official 1.1.1 version and the
second contains the patched version (builds on both windows and
unix platforms).

It was actually who worked on the windows version
of ares and if you have any (off-list) questions, you can email him


Christopher R. Palmer           
Chief Technology Officer        
Vivisimo, Inc.                            412-422-2499
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Received on 2003-07-23