Portability	portable
Stability	provisional
Maintainer	libraries@haskell.org

System.Time

Contents

Clock times
Time differences
Calendar times

Description

The standard Time library, providing standard functionality for clock times, including timezone information (i.e, the functionality of "time.h", adapted to the Haskell environment). It follows RFC 1129 in its use of Coordinated Universal Time (UTC).

Synopsis

Clock times

data ClockTime Source

A representation of the internal clock time. Clock times may be compared, converted to strings, or converted to an external calendar time CalendarTime for I/O or other manipulations.

Constructors

TOD Integer Integer

Construct a clock time. The arguments are a number of seconds since 00:00:00 (UTC) on 1 January 1970, and an additional number of picoseconds.

In Haskell 98, the ClockTime type is abstract.

Instances

Eq ClockTime
Ord ClockTime
Show ClockTime

getClockTime :: IO ClockTime Source

returns the current time in its internal representation.

Time differences

data TimeDiff Source

records the difference between two clock times in a user-readable way.

Constructors

TimeDiff
Fields tdYear :: Int tdMonth :: Int tdDay :: Int tdHour :: Int tdMin :: Int tdSec :: Int tdPicosec :: Integer

Instances

Eq TimeDiff
Ord TimeDiff
Read TimeDiff
Show TimeDiff

noTimeDiff :: TimeDiff Source

null time difference.

diffClockTimes :: ClockTime -> ClockTime -> TimeDiff Source

diffClockTimes t1 t2 returns the difference between two clock times t1 and t2 as a TimeDiff.

addToClockTime :: TimeDiff -> ClockTime -> ClockTime Source

addToClockTime d t adds a time difference d and a clock time t to yield a new clock time. The difference d may be either positive or negative.

normalizeTimeDiff :: TimeDiff -> TimeDiff Source

converts a time difference to normal form.

timeDiffToString :: TimeDiff -> String Source

formats time differences using local conventions.

formatTimeDiff :: TimeLocale -> String -> TimeDiff -> String Source

formats time differences using local conventions and a formatting string. The formatting string is that understood by the ISO C strftime() function.

Calendar times

data CalendarTime Source

CalendarTime is a user-readable and manipulable representation of the internal ClockTime type.

Constructors

CalendarTime

Fields

ctYear :: Int: Year (pre-Gregorian dates are inaccurate)
ctMonth :: Month: Month of the year
ctDay :: Int: Day of the month (1 to 31)
ctHour :: Int: Hour of the day (0 to 23)
ctMin :: Int: Minutes (0 to 59)
ctSec :: Int: Seconds (0 to 61, allowing for up to two leap seconds)
ctPicosec :: Integer: Picoseconds
ctWDay :: Day: Day of the week
ctYDay :: Int: Day of the year (0 to 364, or 365 in leap years)
ctTZName :: String: Name of the time zone
ctTZ :: Int: Variation from UTC in seconds
ctIsDST :: Bool: True if Daylight Savings Time would be in effect, and False otherwise

Instances

Eq CalendarTime
Ord CalendarTime
Read CalendarTime
Show CalendarTime

data Month Source

A month of the year.

Constructors

January
February
March
April
May
June
July
August
September
October
November
December

Instances

Bounded Month
Enum Month
Eq Month
Ord Month
Read Month
Show Month
Ix Month

data Day Source

A day of the week.

Constructors

Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday

Instances

Bounded Day
Enum Day
Eq Day
Ord Day
Read Day
Show Day
Ix Day

toCalendarTime :: ClockTime -> IO CalendarTime Source

converts an internal clock time to a local time, modified by the timezone and daylight savings time settings in force at the time of conversion. Because of this dependence on the local environment, toCalendarTime is in the IO monad.

toUTCTime :: ClockTime -> CalendarTime Source

converts an internal clock time into a CalendarTime in standard UTC format.

toClockTime :: CalendarTime -> ClockTime Source

converts a CalendarTime into the corresponding internal ClockTime, ignoring the contents of the ctWDay, ctYDay, ctTZName and ctIsDST fields.

calendarTimeToString :: CalendarTime -> String Source

formats calendar times using local conventions.

formatCalendarTime :: TimeLocale -> String -> CalendarTime -> String Source

formats calendar times using local conventions and a formatting string. The formatting string is that understood by the ISO C strftime() function.