CURLOPT_SSLENGINE(3)

NAME
CURLOPT_SSLENGINE - Set SSL engine or provider

SYNOPSIS
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLENGINE, char *id);

DESCRIPTION
Pass a pointer to a null-terminated string as parameter. It is used as the identifier for the engine or provider you want to use for your private key. OpenSSL 1 had engines, OpenSSL 3 has providers.

The application does not have to keep the string around after setting this option.

When asking libcurl to use a provider, the application can also optionally provide a property, a set of name value pairs. Such a property can be specified separated from the name with a colon (:).

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again.

DEFAULT
NULL

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

This option works only with the following TLS backends: OpenSSL

EXAMPLE
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    curl_easy_setopt(curl, CURLOPT_SSLENGINE, "dynamic");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

AVAILABILITY
Added in curl 7.9.3

RETURN VALUE
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.

SEE ALSO
CURLINFO_SSL_ENGINES(3), CURLOPT_SSLENGINE_DEFAULT(3), CURLOPT_SSLKEY(3)