CURLOPT_IPRESOLVE(3)

NAME
CURLOPT_IPRESOLVE - IP protocol version to use

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

DESCRIPTION
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:

CURL_IPRESOLVE_WHATEVER
    Default, can use addresses of all IP versions that your system allows.

CURL_IPRESOLVE_V4
    Uses only IPv4 addresses.

CURL_IPRESOLVE_V6
    Uses only IPv6 addresses.

DEFAULT
CURL_IPRESOLVE_WHATEVER

PROTOCOLS
This functionality affects all supported protocols

EXAMPLE
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    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);
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

HISTORY
CURL_IPRESOLVE_* macros became long types in 8.15.0, before this version a long cast was necessary when passed to curl_easy_setopt(3).

AVAILABILITY
Added in curl 7.10.8

RETURN VALUE
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).

SEE ALSO
CURLOPT_HTTP_VERSION(3), CURLOPT_RESOLVE(3), CURLOPT_SSLVERSION(3)