CURLOPT_ADDRESS_SCOPE - Man Page

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ADDRESS_SCOPE, long scope);

Pass a long specifying the scope id value to use when connecting to IPv6 addresses.

0

This functionality affects all supported protocols

#include <net/if.h> /* for if_nametoindex() */

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode ret;
    long my_scope_id;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    my_scope_id = if_nametoindex("eth0");
    curl_easy_setopt(curl, CURLOPT_ADDRESS_SCOPE, my_scope_id);
    ret = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

Added in curl 7.19.0

curl_easy_setopt(3) returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non-zero means an error occurred, see libcurl-errors(3). Returns CURLE_BAD_FUNCTION_ARGUMENT if set to a negative value.

CURLOPT_DEBUGFUNCTION(3), CURLOPT_STDERR(3)

curl_easy_setopt(3), libcurl-symbols(3).