@deftypefun {int} {gnutls_x509_crt_set_subject_key_id} (gnutls_x509_crt_t @var{cert}, const void * @var{id}, size_t @var{id_size})
@var{cert}: a certificate of type @code{gnutls_x509_crt_t} 

@var{id}: The key ID

@var{id_size}: Holds the size of the subject key ID field.

This function will set the X.509 certificate's subject key ID
extension.

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