We do not see the above snippet in the libcurl code. However, We do see following code in function "Curl_getaddrinfo"

  if (pf != PF_INET) {
    /* see if we have an IPv6 stack */
    curl_socket_t s = socket(PF_INET6, SOCK_DGRAM, 0);
    if(s == CURL_SOCKET_BAD) {
      /* Some non-IPv6 stacks have been found to make very slow name resolves
       * when PF_UNSPEC is used, so thus we switch to a mere PF_INET lookup if
       * the stack seems to be a non-ipv6 one. */

      pf = PF_INET;
    }
    else {
      /* This seems to be an IPv6-capable stack, use PF_UNSPEC for the widest
       * possible checks. And close the socket again.
       */
      sclose(s);
    }
  }

This code checks if IPv6 Stack exists but not for case where IPv6 stack exists but is disabled.

---
** [bugs:#1274] IPv6 DNS requests were sent out from Android Handsets even if the IPv6 stack is not present on the device.**
**Status:** pending-needsinfo
**Labels:** dns ipv6 
**Created:** Tue Sep 03, 2013 09:36 PM UTC by Rajiv Dwivedi
**Last Updated:** Tue Sep 17, 2013 08:19 PM UTC
**Owner:** Daniel Stenberg
Observation:
IPv6 DNS requests were sent out from Android Handsets even if the IPv6 stack is not present on the device.
Expected Result:
If there is no IPv6 stack on the device/machine, the IPv6 request should not be sent from the device.
Workaround:
Using option "CURL_IPRESOLVE_V4", disables sending IPv6 DNS queries.
Libcurl details:
OS: Linux - Android
version: 7.32.0
link: http://curl.haxx.se/download.html
Attachments:
Wireshark log ( which displays both Ipv$ and IPv6 records)
Verbose output using libcurl (captured while making HTTP requests)
---
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