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* Copyright (C) 1998 - 2016, 2018, Daniel Stenberg, <daniel@haxx.se>, et al.
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**************************************************************************

CURLOPT_PROXY_SSLVERSION - set preferred proxy TLS/SSL version #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLVERSION, long version); 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: 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_DEFAULT All

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);
}

Added in 7.52.0 Returns CURLE_OK if the option is supported, and CURLE_UNKNOWN_OPTION if not. CURLOPT_USE_SSL "(3), " CURLOPT_HTTP_VERSION "(3), " CURLOPT_IPRESOLVE "(3) " CURLOPT_SSLVERSION "(3), "