anchor.diff:      !!  Set the object calendar and base year
       !!
       !!------------------------------------------------------------
  -    subroutine time_init(this, calendar_name, year_zero, month_zero, day_zero)
  +    subroutine time_init_c(this, calendar_name, year_zero, month_zero, day_zero)
           implicit none
           class(Time_type) :: this
           character(len=*), intent(in) :: calendar_name
  
positive.code:     end function less_than
  
      ! note, this requires the time_delta object
      function difference(time1, time2) result(dt)
          implicit none
          class(Time_type), intent(in) :: time1, time2
          type(time_delta_t) :: dt
  
          call dt%set_time_delta(days=time1%mjd() - time2%mjd())
  
      end function difference
  
  
negative.code:         double precision :: current_date_time = 0
  
        contains
          procedure, public  :: date        => calendar_date
          procedure, public  :: mjd         => get_mjd
          procedure, public  :: day_of_year => calc_day_of_year
          procedure, public  :: date_to_mjd => date_to_mjd
          procedure, public  :: as_string   => as_string
  
          generic,   public  :: init        => time_init_c
          generic,   public  :: init        => time_init_i
          generic,   public  :: set         => set_from_string
          generic,   public  :: set         => set_from_date
          generic,   public  :: set         => set_from_mjd
          procedure, private :: time_init_c
          procedure, private :: time_init_i
          procedure, private :: set_from_string
          procedure, private :: set_from_date
          procedure, private :: set_from_mjd
  