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Re: CURLOPT_TIMEOUT_MS < 1000 - requests not reaching server

From: Daniel Stenberg <>
Date: Fri, 22 Feb 2013 10:31:30 +0100 (CET)

On Wed, 20 Feb 2013, Rakesh Sinha wrote:

> So - adding the following option helped. 
> curl_setopt( $c, CURLOPT_NOSIGNAL, 1);

Yes, since the stock resolver can only be aborted with signals and we use
signal functions with full-second resolution only.

In general, I would say it is of debatable value to have a sub second timeout
when name resolving is involved as well.

> "Consider building libcurl with c-ares support to enable asynchronous DNS
> lookups, which enables nice timeouts for name resolves without signals" 
> My distribution comes prepackages with libcurl .  How would I know , now if
> it has been built with c-ares support though ?  

curl -V shows. But you can also use the threaded resolver to get better
timeout support so you should look for 'AsynchDNS' amoug the features -V

curl_version_info() is the programmatic way to extract the same info.


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Received on 2013-02-22