@deftypefun {int} {gnutls_privkey_sign_data} (gnutls_privkey_t @var{signer}, gnutls_digest_algorithm_t @var{hash}, unsigned int @var{flags}, const gnutls_datum_t * @var{data}, gnutls_datum_t * @var{signature})
@var{signer}: Holds the key

@var{hash}: should be a digest algorithm

@var{flags}: Zero or one of @code{gnutls_privkey_flags_t} 

@var{data}: holds the data to be signed

@var{signature}: will contain the signature allocated with @code{gnutls_malloc()} 

This function will sign the given data using a signature algorithm
supported by the private key. Signature algorithms are always used
together with a hash functions.  Different hash functions may be
used for the RSA algorithm, but only the SHA family for the DSA keys.

You may use @code{gnutls_pubkey_get_preferred_hash_algorithm()}  to determine
the hash algorithm.

@strong{Returns:} On success, @code{GNUTLS_E_SUCCESS}  (0) is returned, otherwise a
negative error value.

@strong{Since:} 2.12.0
@end deftypefun