.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
.\" *
.\" * This software is licensed as described in the file COPYING, which
.\" * you should have received as part of this distribution. The terms
.\" * are also available at https://curl.se/docs/copyright.html.
.\" *
.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell
.\" * copies of the Software, and permit persons to whom the Software is
.\" * furnished to do so, under the terms of the COPYING file.
.\" *
.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
.\" * KIND, either express or implied.
.\" *
.\" * SPDX-License-Identifier: curl
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_IPRESOLVE 3 "19 Jun 2014" libcurl libcurl
.SH NAME
CURLOPT_IPRESOLVE \- IP protocol version to use
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_IPRESOLVE, long resolve);
.fi
.SH 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 host names 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:
.IP CURL_IPRESOLVE_WHATEVER
Default, can use addresses of all IP versions that your system allows.
.IP CURL_IPRESOLVE_V4
Uses only IPv4 addresses.
.IP CURL_IPRESOLVE_V6
Uses only IPv6 addresses.
.SH DEFAULT
CURL_IPRESOLVE_WHATEVER
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
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);
  }
}
.fi
.SH AVAILABILITY
Always
.SH RETURN VALUE
Returns CURLE_OK
.SH "SEE ALSO"
.BR CURLOPT_HTTP_VERSION (3),
.BR CURLOPT_RESOLVE (3),
.BR CURLOPT_SSLVERSION (3)