Re: Curl timeout option in milliseconds

Hi Daniel,

Correct me if I am wrong. Using
 --enable-ares=<ares installation path> should help to achieve timeout <
1000.

Also if there is any documentation on installing c-ares and building
libcurl with c-ares, please share here.

Thanks and regards
Karthikeyan T S.

On Sat, 16 Nov 2019, 16:53 karthikeyan Sivakkumar, <tsk.karthik_at_gmail.com>
wrote:

> Hi Daniel,
>
> Thanks for the clarification. Apologies for missing out to answer your
> backend resolver query. Libcurl build is actually done by our application
> product and I donot have the info with me.
>
> Will check with them.
>
> I did check your blog on libcurls-name-resolving and got some info about
> the c-ares and threaded solutions for asynchronous name resolving.
>
> Looking at curl docs, I learnt about the - - disable-ares option to
> disable C-ARES support thereby reducing libcurl size. I can check with my
> product team if this option was used in our libcurl build.
>
> Kindly guide me if this would help. Also, if there is anyother way to
> enable the async/threaded resolving, kindly let me know the same too.
>
>
> Thanks and regards,
> Karthikeyan T S.
>
> On Fri, 15 Nov 2019, 19:24 Daniel Stenberg, <daniel_at_haxx.se> wrote:
>
>>
>> > Cases 1, 2 and 3 work fine but timeout occurs wrongly in cases 4 and 5.
>> > Please correct me if my understanding here is wrong.
>>
>> Didn't this change the behavior? Your original statement said sub second
>> timeouts still took a full second but in this output it looks like they
>> failed
>> completely.
>>
>> You also never answered my question about what resolver backend your
>> build is
>> using but I think that the above behavior answers it for me with enough
>> certainty:
>>
>> I think libcurl returns an error for you due to this condition:
>>
>>
>> https://github.com/curl/curl/blob/c6b70de24660673648a37be4d18638274d7f5741/lib/hostip.c#L662-L669
>>
>> ... this is because you've built libcurl to use the synchronous name
>> resolver
>> and we can only time-out that with signal() and that function only has
>> integer
>> second resolution. If you ask for a shorter timeout, that can't be
>> fullfilled.
>>
>> libcurl defaults to using the threaded resolver these days which will
>> fire up
>> the resolver in a sepearate thread that can be abandonded easier and in
>> less
>> than a second.
>>
>> --
>>
>> / daniel.haxx.se | Get the best commercial curl support there is -
>> from me
>> | Private help, bug fixes, support, ports, new features
>> | https://www.wolfssl.com/contact/
>>
>

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Received on 2019-11-16