NAME

       CURLOPT_PROXY_SSLVERSION - preferred HTTPS proxy TLS version

SYNOPSIS

       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLVERSION,
                                 long version);

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:

       CURL_SSLVERSION_DEFAULT
              The default action. This attempts to figure out the remote SSL protocol version.

       CURL_SSLVERSION_TLSv1
              TLSv1.x

       CURL_SSLVERSION_TLSv1_0
              TLSv1.0

       CURL_SSLVERSION_TLSv1_1
              TLSv1.1

       CURL_SSLVERSION_TLSv1_2
              TLSv1.2

       CURL_SSLVERSION_TLSv1_3
              TLSv1.3

       The maximum TLS version can be set by using one of the CURL_SSLVERSION_MAX_ macros  below.
       It  is  also  possible  to  OR  one  of  the  CURL_SSLVERSION_  macros  with  one  of  the
       CURL_SSLVERSION_MAX_ macros. The MAX macros are not supported for wolfSSL.

       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)

       CURL_SSLVERSION_MAX_TLSv1_0
              The flag defines maximum supported TLS version as TLSv1.0.  (Added in 7.54.0)

       CURL_SSLVERSION_MAX_TLSv1_1
              The flag defines maximum supported TLS version as TLSv1.1.  (Added in 7.54.0)

       CURL_SSLVERSION_MAX_TLSv1_2
              The flag defines maximum supported TLS version as TLSv1.2.  (Added in 7.54.0)

       CURL_SSLVERSION_MAX_TLSv1_3
              The flag defines maximum supported TLS version as TLSv1.3.  (Added in 7.54.0)

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

DEFAULT

       CURL_SSLVERSION_DEFAULT

PROTOCOLS

       This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

       All TLS backends support this option.

EXAMPLE

       int main(void)
       {
         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);
         }
       }

AVAILABILITY

       Added in curl 7.52.0

RETURN VALUE

       Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not.

SEE ALSO

       CURLOPT_HTTP_VERSION(3), CURLOPT_IPRESOLVE(3), CURLOPT_SSLVERSION(3), CURLOPT_USE_SSL(3)