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Re: libcurl function to specify IP address of webserver (bypassing DNS)

From: Daniel Stenberg <>
Date: Wed, 16 Jul 2003 11:44:52 +0200 (CEST)

On Wed, 16 Jul 2003, jose wrote:

> > I don't think this is a feture we need to add to libcurl, as you can make
> > this happen perfectly easy all by yourself. Yes, it requires you to parse
> > and "fix" the URL yourself, but it still is a pretty weird operation...
> Any app that wants to get performance with Curl needs to bypass the Curl
> sync DNS queries and currently this has not received much attention.

Well, I don't quite agree with your statements. First, I think you can get
quite good performance with curl even though it looks up names synchronously,
and secondly, it has gotten some attention.

The problem is probably that mere "attention" doesn't bring us forward in this
matter. Only code and ideas on how to do the code do.

> Any ideas on how to do this effectively would be very useful to many users.
> Given that libdenise (Curl asynch DNS sister library) is not progressing, it
> would be helpful to show how Curl could be easily interface with glibc
> asynch DNS.

The best way to do progress on this would be to make libdenise move forward,

IIRC, the async stuff in the glibc name lookups are: 1) badly documented and
2) based on signals. The signal dependency effectively kills the ability to
use this with threads. Not to mention that glibc isn't very portable outside
Linux boxes.

 Daniel Stenberg -- curl: been grokking URLs since 1998
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Received on 2003-07-16