@deftypefun {time_t} {gnutls_x509_crt_get_expiration_time} (gnutls_x509_crt_t @var{cert})
@var{cert}: should contain a @code{gnutls_x509_crt_t}  type

This function will return the time this certificate was or will be
expired.

@strong{Returns:} expiration time, or (time_t)-1 on error.
@end deftypefun