**************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
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* Copyright (C) 1998 - 2017, Daniel Stenberg, <daniel@haxx.se>, et al.
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* 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.
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**************************************************************************

CURLOPT_SSLENGINE - set SSL engine identifier #include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLENGINE, char *id); Pass a pointer to a null-terminated string as parameter. It will be used as the identifier for the crypto engine you want to use for your private key. The application does not have to keep the string around after setting this option. NULL All TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

CURL *curl = curl_easy_init();
if(curl) {
 curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
 curl_easy_setopt(curl, CURLOPT_SSLENGINE, "dynamic");
 ret = curl_easy_perform(curl);
 curl_easy_cleanup(curl);
}

Only if the SSL backend is OpenSSL built with engine support. CURLE_OK - Engine found. CURLE_SSL_ENGINE_NOTFOUND - Engine not found, or OpenSSL was not built with engine support. CURLE_SSL_ENGINE_INITFAILED - Engine found but initialization failed. CURLE_NOT_BUILT_IN - Option not built in, OpenSSL is not the SSL backend. CURLE_UNKNOWN_OPTION - Option not recognized. CURLE_OUT_OF_MEMORY - Insufficient heap space. CURLOPT_SSLENGINE_DEFAULT "(3), " CURLOPT_SSLKEY "(3), "