CURLOPT_IPRESOLVE(3) Library Functions Manual CURLOPT_IPRESOLVE(3)

CURLOPT_IPRESOLVE - IP protocol version to use

#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IPRESOLVE, long resolve);

Allows an application to select what kind of IP addresses to use when establishing a connection or choosing one from the connection pool. This is interesting when using hostnames that resolve to more than one IP family.

If the URL provided for a transfer contains a numerical IP version as a host name, this option does not override or prohibit libcurl from using that IP version.

Available values for this option are:

Default, can use addresses of all IP versions that your system allows.
Uses only IPv4 addresses.
Uses only IPv6 addresses.

CURL_IPRESOLVE_WHATEVER

All

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");
    /* of all addresses example.com resolves to, only IPv6 ones are used */
    curl_easy_setopt(curl, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V6);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

Always

Returns CURLE_OK

CURLOPT_HTTP_VERSION(3), CURLOPT_RESOLVE(3), CURLOPT_SSLVERSION(3)

2024-05-22 libcurl