1# //base: Time-Related Functionality 2 3This directory contains the portions of //base that deal with time-related 4concepts. Most critical are the classes in [time.h](time.h). `Time` and 5`TimeTicks` both encode absolute times, but `TimeTicks` is monotonic and should 6be used for most internal purposes, while `Time` can move backwards and is 7primarily for human-readable times. `TimeDelta` is a duration computed from 8either of the above concepts. 9 10There are also various files dealing with clocks, which are primarily useful 11when tests need to modify how the program tracks the passage of time. See 12[/base/test/task_environment.h](/base/test/task_environment.h)'s `MOCK_TIME` 13ability for 14[testing components which post tasks](/docs/threading_and_tasks_testing.md). 15