A Time::Clock object is a twenty-four hour clock with nanosecond precision and wrap-around. It is a clock only; it has absolutely no concept of dates. Vagaries of date/time such as leap seconds and daylight savings time are unsupported. When a Time::Clock object hits 23:59:59.999999999 and at least one more nanosecond is added, it will wrap around to 00:00:00.000000000. This works in reverse when time is subtracted. Time::Clock objects automatically stringify to a user-definable format.