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Re: HTTPS and Multi-threading

From: Daniel Stenberg <>
Date: Tue, 8 Jun 2004 23:32:11 +0200 (CEST)

On Tue, 8 Jun 2004, Olano, Ever wrote:

> 1. In the guide, it says "When using multiple threads you should first
> ignore SIGPIPE in your main thread and set the CURLOPT_NOSIGNAL option to
> TRUE for all handles." How do I ignore SIGPIPE in my main thread? (I warned
> you about newbie stuff). Or is that still needed?

I don't think so, that info is slightly outdated. On most platforms libcurl
should inhibit the SIGPIPE.

> I'm actually building a C library for our customers. So the main thread
> would be theirs, unfortunately. Do library providers usually ask their
> customers to do this in their app?

I don't know.

> 2. What would not enabling ares-support exactly cause?

You won't be able to do name resolve timeouts accurately.

> If I don't have ares-support enabled and dns-resolves take too long, would
> the application hang?


> Or would it crash?


> What exactly happens?

ares is the way we do asynch name resolves. Without asynch we use synch. If a
synchronous name resolve call takes a long time, it won't return until that
time has passed (since cancelling it would require the use of a signal). It
hangs until done.

> Do people usually find themselves building with ares-support?

I would estimate that most people don't.

> 3. If I enable ares-support, do I need to download and build ares myself or
> is it included in curl.

You download, build and install it separately first. Then you build curl and
enable ares-support.

> 5. Have you or anyone tried using the sample code in mttest.c?

What's that?

> 6. It seems I have to set these callback functions in the main thread too
> (before any threads are spawned, I guess). Again, my problem is that I'm
> building a library to be used by our customers. Should I make them set
> these in their code?

Possibly, it pretty much depends on what API you provide to your customers.

     Daniel Stenberg -- --
      Dedicated custom curl help for hire:
Received on 2004-06-08