@deftypefun {void} {gnutls_certificate_set_params_function} (gnutls_certificate_credentials_t @var{res}, gnutls_params_function * @var{func})
@var{res}: is a gnutls_certificate_credentials_t type
@var{func}: is the function to be called
This function will set a callback in order for the server to get
the Diffie-Hellman or RSA parameters for certificate
authentication. The callback should return @code{GNUTLS_E_SUCCESS} (0) on success.
@strong{Deprecated:} This function is unnecessary and discouraged on GnuTLS 3.6.0
or later. Since 3.6.0, DH parameters are negotiated
following RFC7919.
@end deftypefun