.\" **************************************************************************
.\" *                                  _   _ ____  _
.\" *  Project                     ___| | | |  _ \| |
.\" *                             / __| | | | |_) | |
.\" *                            | (__| |_| |  _ <| |___
.\" *                             \___|\___/|_| \_\_____|
.\" *
.\" * Copyright (C) 1998 - 2019, 2018, 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.haxx.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.
.\" *
.\" **************************************************************************
.\"
.TH CURLOPT_PROXY_SSLVERSION 3 "16 Nov 2016" "libcurl 7.52.0" "curl_easy_setopt options"
.SH NAME
CURLOPT_PROXY_SSLVERSION \- set preferred proxy TLS/SSL version
.SH SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLVERSION, long version);
.SH DESCRIPTION
Pass a long as parameter to control which version of SSL/TLS to attempt to use
when connecting to an HTTPS proxy.

Use one of the available defines for this purpose. The available options are:
.RS
.IP CURL_SSLVERSION_DEFAULT
The default action. This will attempt to figure out the remote SSL protocol
version.
.IP CURL_SSLVERSION_TLSv1
TLSv1.x
.IP CURL_SSLVERSION_TLSv1_0
TLSv1.0
.IP CURL_SSLVERSION_TLSv1_1
TLSv1.1
.IP CURL_SSLVERSION_TLSv1_2
TLSv1.2
.IP CURL_SSLVERSION_TLSv1_3
TLSv1.3
.RE
The maximum TLS version can be set by using \fIone\fP of the
CURL_SSLVERSION_MAX_ macros below. It is also possible to OR \fIone\fP of the
CURL_SSLVERSION_ macros with \fIone\fP of the CURL_SSLVERSION_MAX_ macros.
The MAX macros are not supported for WolfSSL.
.RS
.IP CURL_SSLVERSION_MAX_DEFAULT
The flag defines the maximum supported TLS version as TLSv1.2, or the default
value from the SSL library.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_0
The flag defines maximum supported TLS version as TLSv1.0.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_1
The flag defines maximum supported TLS version as TLSv1.1.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_2
The flag defines maximum supported TLS version as TLSv1.2.
(Added in 7.54.0)
.IP CURL_SSLVERSION_MAX_TLSv1_3
The flag defines maximum supported TLS version as TLSv1.3.
(Added in 7.54.0)
.RE

In versions of curl prior to 7.54 the CURL_SSLVERSION_TLS options were
documented to allow \fIonly\fP the specified TLS version, but behavior was
inconsistent depending on the TLS library.

.SH DEFAULT
CURL_SSLVERSION_DEFAULT
.SH PROTOCOLS
All
.SH EXAMPLE
.nf
CURL *curl = curl_easy_init();
if(curl) {
  curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

  /* ask libcurl to use TLS version 1.0 or later */
  curl_easy_setopt(curl, CURLOPT_SSLVERSION, CURL_SSLVERSION_TLSv1);

  /* Perform the request */
  curl_easy_perform(curl);
}
.fi
.SH AVAILABILITY
Added in 7.52.0
.SH RETURN VALUE
Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.
.SH "SEE ALSO"
.BR CURLOPT_USE_SSL "(3), " CURLOPT_HTTP_VERSION "(3), "
.BR CURLOPT_IPRESOLVE "(3) " CURLOPT_SSLVERSION "(3), "