.SH EXAMPLE
TODO
.SH AVAILABILITY
-This option is OpenSSL-specific and does nothing if libcurl is built to use
-GnuTLS. NSS-powered libcurl provides the option only for backward
-compatibility.
+This option is supported by the OpenSSL, GnuTLS and PolarSSL backends. The NSS
+backend provides the option only for backward compatibility.
.SH RETURN VALUE
Returns CURLE_OK if TLS enabled, and CURLE_UNKNOWN_OPTION if not, or
CURLE_OUT_OF_MEMORY if there was insufficient heap space.