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Re: [EXTERNAL] Re: Feature request: provide ability to set a global callback function telling libcurl if IPv6 works on the system

From: Dan Fandrich via curl-library <>
Date: Tue, 20 Sep 2022 13:42:03 -0700

On Tue, Sep 20, 2022 at 08:28:10PM +0000, Dmitry Karpov wrote:
> Yes, I want to use dual-stack in general. That's why my application has numerous components which use CURLOPT_IPRESOLVE = AUTO.
> But if IPv6 doesn't work on a "system level", I want my curl code to be as fast as "IPv4 only" resolve mode without changing anything in my code - like doing detection that IPv6 doesn't work and modifying IP resolve mode in all the places where I create and set an easy handle (that's your suggestion as I understood it).

I still haven't seen any reason this needs to be a callback, besides that it's
easier to integrate into your program. If you insist on this being a callback,
then you can just call it yourself by changing your code from using
curl_easy_init() everywhere to using dmitry_curl_easy_init():

CURL *dmitry_curl_easy_init(void) {
  CURL *c=curl_easy_init();
  return c;

libcurl doesn't need a new callback mechanism to do this.

Received on 2022-09-20