Data.Time.Clock

Get the number of picoseconds in a DiffTime.

Create a DiffTime from a number of picoseconds.

Create a DiffTime which represents an integral number of seconds.

One day in NominalDiffTime.

Get the seconds in a NominalDiffTime.

Create a NominalDiffTime from a number of seconds.

The resolution of getSystemTime, getCurrentTime, getPOSIXTime. On UNIX systems this uses clock_getres, which may be wrong on WSL2.

addUTCTime a b = a + b

diffUTCTime a b = a - b

Get the current UTCTime from the system clock.

This is a length of time, as measured by a clock. Conversion functions such as fromInteger and realToFrac will treat it as seconds. For example, (0.010 :: DiffTime) corresponds to 10 milliseconds.

It has a precision of one picosecond (= 10^-12 s). Enumeration functions will treat it as picoseconds.

This is a length of time, as measured by UTC. It has a precision of 10^-12 s.

Conversion functions such as fromInteger and realToFrac will treat it as seconds. For example, (0.010 :: NominalDiffTime) corresponds to 10 milliseconds.

It has a precision of one picosecond (= 10^-12 s). Enumeration functions will treat it as picoseconds.

It ignores leap-seconds, so it's not necessarily a fixed amount of clock time. For instance, 23:00 UTC + 2 hours of NominalDiffTime = 01:00 UTC (+ 1 day), regardless of whether a leap-second intervened.

This is the simplest representation of UTC. It consists of the day number, and a time offset from midnight. Note that if a day has a leap second added to it, it will have 86401 seconds.

The Modified Julian Date is the day with the fraction of the day, measured from UT midnight. It's used to represent UT1, which is time as measured by the earth's rotation, adjusted for various wobbles.