Date and Time Support

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This topic lists all types, routines, and variables that add Date and Time support.

Date and Time Data Types

The following table lists the data types used to store date and time:

Type	Description
System.TDate	TDate is used to represent a date.
System.TDateTime	TDateTime represents a date-and-time value in the Delphi language.
System.SysUtils.TTimeStamp	TTimeStamp represents time and date values.
System.TTime	TTime is used to represent a time.
System.DateUtils.TTimeZone	Provides support for a time zone.

Obtaining current Date and Time

The following table lists all routines used to obtain current date and time:

Routine	Description
System.SysUtils.CurrentYear	Returns the current year.
System.SysUtils.Date	Returns the current date.
System.SysUtils.DayOfWeek	Returns the day of the week for a specified date.
System.SysUtils.GetTime	Returns the current time.
System.SysUtils.Now	Returns the current date and time.
System.SysUtils.Time	Returns the current time.
System.DateUtils.Today	Returns a TDateTime value that represents the current date.
System.DateUtils.Tomorrow	Returns a TDateTime value that represents the following day.
System.DateUtils.Yesterday	Returns a TDateTime value that represents the preceding day.

Creating Date and Time values

The following table lists all routines used to create date and time values:

Routine	Description
System.SysUtils.EncodeDate	Returns a TDateTime value that represents a specified year, month, and day.
System.DateUtils.EncodeDateDay	Returns a TDateTime value that represents a specified day of the year for a specified year.
System.DateUtils.EncodeDateMonthWeek	Returns a TDateTime value that represents a specified day of a specified week in a specified month and year.
System.DateUtils.EncodeDateTime	Returns a TDateTime value that represents a specified year, month, day, hour, minute, second, and millisecond.
System.DateUtils.EncodeDateWeek	Returns a TDateTime value that represents a specified day of a specified week in a specified year.
System.DateUtils.EncodeDayOfWeekInMonth	Returns a TDateTime value that represents a specified occurrence of a day of the week within a specified month and year.
System.SysUtils.EncodeTime	Returns a TDateTime value for a specified hour, minute, second, and millisecond.
System.SysUtils.TryEncodeDate	Creates a TDateTime value that represents a specified year, month, and day.
System.DateUtils.TryEncodeDateDay	Calculates the TDateTime value that represents a specified day of the year for a specified year.
System.DateUtils.TryEncodeDateMonthWeek	Calculates the TDateTime value that represents a specified day of a specified week in a specified month and year.
System.DateUtils.TryEncodeDateTime	Calculates the TDateTime value that represents a specified year, month, day, hour, minute, second, and millisecond.
System.DateUtils.TryEncodeDateWeek	Calculates the TDateTime value that represents a specified day of a specified week in a specified year.
System.DateUtils.TryEncodeDayOfWeekInMonth	Calculates a TDateTime value that represents a specified occurrence of a day of the week within a specified month and year.
System.SysUtils.TryEncodeTime	Creates a TDateTime value for a specified hour, minute, second, and millisecond.

Extracting information from date and time values

The following table lists all routines used to extract specific parts out of date and time values:

Routine	Description
System.DateUtils.DateOf	Strips the time portion from a TDateTime value.
System.DateUtils.DayOf	Returns the day of the month represented by a TDateTime value.
System.DateUtils.DayOfTheMonth	Returns the day of the month represented by a TDateTime value.
System.DateUtils.DayOfTheWeek	Returns the day of the week represented by a TDateTimevalue.
System.DateUtils.DayOfTheYear	Returns the number of days between a specified TDateTime value and December 31 of the previous year.
System.SysUtils.DecodeDate	Returns Year, Month, and Day values for a TDateTime value.
System.DateUtils.DecodeDateDay	Returns the year and day of the year for a specified TDateTime value.
System.SysUtils.DecodeDateFully	Returns Year, Month, Day, and Day-of-Week values for a TDateTime value.
System.DateUtils.DecodeDateMonthWeek	Returns the year, month, week of the month, and day of the week for a specified TDateTime value.
System.DateUtils.DecodeDateTime	Returns Year, Month, Day, Hour, Minute, Second, and Millisecond values for a specified TDateTime value.
System.DateUtils.DecodeDateWeek	Returns the year, week of the year, and day of the week for a specified TDateTime value.
System.DateUtils.DecodeDayOfWeekInMonth	For a given TDateTime value, returns the year, month, day of the week, and the count of that day of the week in the month.
System.SysUtils.DecodeTime	Breaks a TDateTime value into hours, minutes, seconds, and milliseconds.
System.DateUtils.HourOf	Returns the hour of the day represented by a TDateTime value.
System.DateUtils.HourOfTheDay	Returns the hour of the day represented by a TDateTime value.
System.DateUtils.HourOfTheMonth	Returns the number of hours between a specified TDateTime value and 12:00 A.M. of the first day of the month.
System.DateUtils.HourOfTheWeek	Returns the number of hours between a specified TDateTime value and 12:00 A.M. of the first day of the week.
System.DateUtils.HourOfTheYear	Returns the number of hours between a specified TDateTime value and 12:00 A.M. of the first day of the year.
System.DateUtils.MilliSecondOf	Returns the millisecond of the second represented by a TDateTime value.
System.DateUtils.MilliSecondOfTheDay	Returns the number of milliseconds between a specified TDateTime value and the beginning of the same day.
System.DateUtils.MilliSecondOfTheHour	Returns the number of milliseconds between a specified TDateTime value and the beginning of the same hour.
System.DateUtils.MilliSecondOfTheMinute	Returns the number of milliseconds between a specified TDateTime value and the beginning of the same minute.
System.DateUtils.MilliSecondOfTheMonth	Returns the number of milliseconds between a specified TDateTime value and the beginning of the month.
System.DateUtils.MilliSecondOfTheSecond	Returns the millisecond of the second represented by a TDateTime value.
System.DateUtils.MilliSecondOfTheWeek	Returns the number of milliseconds between a specified TDateTime value and 12:00:00:00 A.M. of the first day of the week.
System.DateUtils.MilliSecondOfTheYear	Returns the number of milliseconds between a specified TDateTime value and 12:00:00:00 A.M. of the first day of the year.
System.DateUtils.MinuteOf	Returns the minute of the hour represented by a TDateTime value.
System.DateUtils.MinuteOfTheDay	Returns the number of minutes between a specified TDateTime value and 12:00 A.M. of the same day.
System.DateUtils.MinuteOfTheHour	Returns the number of minutes between a specified TDateTime value and the beginning of the same hour.
System.DateUtils.MinuteOfTheMonth	Returns the number of minutes between a specified TDateTime value and 12:00 A.M. of the first day of the month.
System.DateUtils.MinuteOfTheWeek	Returns the number of minutes between a specified TDateTime value and 12:00 A.M. of the first day of the week.
System.DateUtils.MinuteOfTheYear	Returns the number of minutes between a specified TDateTime value and 12:00 A.M. of the first day of the year.
System.DateUtils.MonthOf	Returns the month of the year represented by a TDateTime value.
System.DateUtils.MonthOfTheYear	Returns the month of the year represented by a TDateTime value.
System.DateUtils.NthDayOfWeek	Returns the weekday of the specified TDateTime value.
System.DateUtils.SecondOf	Returns the second of the minute represented by a TDateTime value.
System.DateUtils.SecondOfTheDay	Returns the number of seconds between a specified TDateTime value and 12:00:00 A.M. of the same day.
System.DateUtils.SecondOfTheHour	Returns the number of seconds between a specified TDateTime value and the beginning of the same hour.
System.DateUtils.SecondOfTheMinute	Returns the number of seconds between a specified TDateTime value and the beginning of the same minute.
System.DateUtils.SecondOfTheMonth	Returns the number of seconds between a specified TDateTime value and 12:00:00 A.M. on the first day of the month.
System.DateUtils.SecondOfTheWeek	Returns the number of seconds between a specified TDateTime value and 12:00:00 A.M. of the first day of the week.
System.DateUtils.SecondOfTheYear	Returns the number of seconds between a specified STDateTime value and 12:00:00 A.M. on the first day of the year.
System.DateUtils.TimeOf	Strips the date portion from a TDateTime value.
System.DateUtils.WeekOf	Returns the week of the year represented by a TDateTime value.
System.DateUtils.WeekOfTheMonth	Returns the week of the month represented by a TDateTime value.
System.DateUtils.WeekOfTheYear	Returns the week of the year represented by a TDateTime value.
System.DateUtils.WeeksInAYear	Returns the number of weeks in a specified year.
System.DateUtils.WeeksInYear	Returns the number of weeks in the year of a specified TDateTime value.
System.DateUtils.YearOf	Returns the year represented by a TDateTime value.

Comparing and Checking Date and Time values

The following table lists all routines used to compare and check date and time values:

Routine	Description
System.DateUtils.CompareDate	Indicates the relationship between the date portions of two TDateTime values.
System.DateUtils.CompareDateTime	Indicates the relationship between two TDateTime values.
System.DateUtils.CompareTime	Indicates the relationship between the time portions of two TDateTime values.
System.DateUtils.IsInLeapYear	Indicates whether a specified TDateTime value occurs in a leap year.
System.DateUtils.IsAM	Indicates whether the time portion of a specified TDateTime value occurs before noon.
System.DateUtils.IsPM	Indicates whether the time portion of a specified TDateTime value occurs after noon.
System.DateUtils.IsSameDay	Indicates whether a specified TDateTime value occurs on the same day as a criterion date.
System.DateUtils.IsToday	Indicates whether a specified TDateTime value occurs on the current date.
System.DateUtils.IsValidDate	Indicates whether a specified year, month, and day represent a valid date.
System.DateUtils.IsValidDateDay	Indicates whether a specified year and day of the year represent a valid date.
System.DateUtils.IsValidDateMonthWeek	Indicates whether a specified year, month, week of the month, and day of the week represent a valid date.
System.DateUtils.IsValidDateTime	Indicates whether a specified year, month, day, hour, minute, second, and millisecond represent a valid date and time.
System.DateUtils.IsValidDateWeek	Indicates whether a specified year, week of the year, and day of the week represent a valid date.
System.DateUtils.IsValidTime	Indicates whether a specified hour, minute, second, and millisecond represent a valid date and time.
System.DateUtils.SameDate	Indicates whether two TDateTime values represent the same year, month, and day.
System.DateUtils.SameDateTime	Indicates whether two TDateTime values represent the same year, month, day, hour, minute, second, and millisecond.
System.DateUtils.SameTime	Indicates whether two TDateTime values represent the same time of day, ignoring the date portion.
System.DateUtils.WithinPastDays	Indicates whether two dates are within a specified number of days of each other.
System.DateUtils.WithinPastHours	Indicates whether two date/time values are within a specified number of hours of each other.
System.DateUtils.WithinPastMilliSeconds	Indicates whether two date/time values are within a specified number of milliseconds of each other.
System.DateUtils.WithinPastMinutes	Indicates whether two date/time values are within a specified number of minutes of each other.
System.DateUtils.WithinPastMonths	Indicates whether two date/time values are within a specified number of months of each other.
System.DateUtils.WithinPastSeconds	Indicates whether two date/time values are within a specified number of seconds of each other.
System.DateUtils.WithinPastWeeks	Indicates whether two date/time values are within a specified number of weeks of each other.
System.DateUtils.WithinPastYears	Indicates whether two date/time values are within a specified number of years of each other.
System.DateUtils.DateInRange	Checks whether a TDate value is in a given range.
System.DateUtils.DateTimeInRange	Checks whether a TDateTime value is in a given range.

Calculations on Date and Time values

The following table lists all routines used to perform calculations on Date and Time values:

Routine	Description
System.DateUtils.DaySpan	Returns the number of days (including fractional days) between two specified TDateTime values.
System.DateUtils.DaysBetween	Returns the number of whole days between two specified TDateTime values.
System.DateUtils.DaysInAMonth	Returns the number of days in a specified month of a specified year.
System.DateUtils.DaysInAYear	Returns the number of days in a specified year.
System.DateUtils.DaysInMonth	Returns the number of days in the month of a specified TDateTime value.
System.DateUtils.DaysInYear	Returns the number of days in the year of a specified TDateTime value.
System.DateUtils.EndOfADay	Returns a TDateTime that represents the last millisecond of a specified day.
System.DateUtils.EndOfAMonth	Returns a TDateTime that represents the last millisecond of the last day of a specified month.
System.DateUtils.EndOfAWeek	Returns a TDateTime object value that represents the last millisecond of a specified day of a specified week.
System.DateUtils.EndOfAYear	Returns a TDateTime that represents the last millisecond of a specified year.
System.DateUtils.EndOfTheDay	Returns a TDateTime that represents the last millisecond of the day identified by a specified TDateTime.
System.DateUtils.EndOfTheMonth	Returns a TDateTime that represents the last millisecond of the last day of the month identified by a specified TDateTime.
System.DateUtils.EndOfTheWeek	Returns a TDateTime that represents the last millisecond of the last day of the week identified by a specified TDateTime.
System.DateUtils.EndOfTheYear	Returns a TDateTime that represents the last millisecond of the last day of the year identified by a specified TDateTime.
System.DateUtils.HourSpan	Returns the number of hours (including fractional hours) between two specified TDateTime values.
System.DateUtils.HoursBetween	Returns the number of whole hours between two specified TDateTime values.
System.SysUtils.IncAMonth	Increments date information by one month.
System.DateUtils.IncDay	Returns a date shifted by a specified number of days.
System.DateUtils.IncHour	Returns a date/time value shifted by a specified number of hours.
System.DateUtils.IncMilliSecond	Returns a date/time value shifted by a specified number of milliseconds.
System.DateUtils.IncMinute	Returns a date/time value shifted by a specified number of minutes.
System.SysUtils.IncMonth	Returns a date shifted by a specified number of months.
System.DateUtils.IncSecond	Returns a date/time value shifted by a specified number of seconds.
System.DateUtils.IncWeek	Returns a date shifted by a specified number of weeks.
System.DateUtils.IncYear	Returns a date shifted by a specified number of years.
System.DateUtils.MilliSecondSpan	Returns the number of milliseconds between two specified TDateTime values.
System.DateUtils.MilliSecondsBetween	Returns the number of milliseconds between two specified TDateTime values.
System.DateUtils.MinuteSpan	Returns the number of minutes, including fractions thereof, between two specified TDateTime values.
System.DateUtils.MinutesBetween	Returns the number of minutes between two specified TDateTime values.
System.DateUtils.MonthSpan	Returns the approximate number of months, including fractions, between two specified TDateTime values.
System.DateUtils.MonthsBetween	Returns the approximate number of months between two specified TDateTime values.
System.DateUtils.RecodeDate	Replaces the date portion of a specified TDateTimee value.
System.DateUtils.RecodeDateTime	Selectively replaces parts of a specified TDateTimevalue.
System.DateUtils.RecodeDay	Replaces the day of the month for a specified TDateTime value.
System.DateUtils.RecodeHour	Replaces the hour of the day for a specified TDateTime value.
System.DateUtils.RecodeMilliSecond	Replaces the millisecond of the second for a specified TDateTime value.
System.DateUtils.RecodeMinute	Replaces the minute of the hour for a specified TDateTime value.
System.DateUtils.RecodeMonth	Replaces the month of the year for a specified TDateTime value.
System.DateUtils.RecodeSecond	Replaces the second of the minute for a specified TDateTime value.
System.DateUtils.RecodeTime	Replaces the time portion of a specified TDateTime value.
System.DateUtils.RecodeYear	Replaces the year for a specified TDateTime value.
System.DateUtils.SecondSpan	Returns the number of seconds (including fractions thereof) between two specified TDateTime values.
System.DateUtils.SecondsBetween	Returns the number of seconds between two specified TDateTime values.
System.DateUtils.StartOfADay	Returns a TDateTime that represents 12:00:00:00 A.M. on a specified day.
System.DateUtils.StartOfAMonth	Returns a TDateTime that represents 12:00:00:00 A.M. on the first day of a specified month.
System.DateUtils.StartOfAWeek	Returns a TDateTime that represents the first moment on a specified day of a specified week.
System.DateUtils.StartOfAYear	Returns a TDateTime that represents the first moment on the first day of a specified year.
System.DateUtils.StartOfTheDay	Returns a TDateTime that represents 12:00:00:00 A.M. on the day identified by a specified TDateTime.
System.DateUtils.StartOfTheMonth	Returns a TDateTime that represents 12:00:00:00 A.M. on the first day of the month identified by a specified TDateTime.
System.DateUtils.StartOfTheWeek	Returns a TDateTime that represents 12:00:00:00 A.M. on the first day of the week identified by a specified TDateTime.
System.DateUtils.StartOfTheYear	Returns a TDateTime that represents 12:00:00:00 A.M. on the first day of the year identified by a specified TDateTime.
System.DateUtils.WeekSpan	Returns the number of weeks (including fractional weeks) between two specified TDateTime values.
System.DateUtils.WeeksBetween	Returns the number of whole weeks between two specified TDateTime values.
System.DateUtils.YearSpan	Returns the approximate number of years (including fractions thereof) between two specified TDateTime values.
System.DateUtils.YearsBetween	Returns the approximate number of years between two specified TDateTime values.

Converting Date and Time values

The following table lists all routines used to convert to or from date and time values:

Routine	Description
System.DateUtils.DateToISO8601	Converts a date-and-time value, specified in the TDateTime format, into the ISO 8601 format.
System.SysUtils.DateTimeToFileDate	Converts a TDateTime value to an OS timestamp value.
System.DateUtils.DateTimeToJulianDate	Converts a TDateTime value into a Julian date.
System.DateUtils.DateTimeToModifiedJulianDate	Converts a TDateTime value into a modified Julian date.
System.SysUtils.DateTimeToStr	Converts a TDateTime value to a string, using the local settings for displaying date and time.
System.SysUtils.DateTimeToString	Converts a TDateTime value to a string, using a specified SysUtils.Format.
System.SysUtils.DateTimeToSystemTime	Converts a TDateTime value into the Win32 API's system time type.
System.SysUtils.DateTimeToTimeStamp	Converts a TDateTime value into the corresponding TTimeStamp value.
System.DateUtils.DateTimeToUnix	Converts a TDateTime value into a Unix/Linux-style date-and-time value.
System.SysUtils.DateToStr	Converts a TDateTime value to a string.
System.DateUtils.ISO8601ToDate	Converts a date-and-time value, specified in the ISO 8601 format, into the TDateTime format.
System.DateUtils.JulianDateToDateTime	Converts a Julian date to a TDateTime value.
System.SysUtils.MSecsToTimeStamp	Converts a specified number of milliseconds into a TTimeStamp value.
System.DateUtils.ModifiedJulianDateToDateTime	Converts a modified Julian date to a TDateTime value.
System.SysUtils.StrToDate	Converts a string to a TDateTime value.
System.SysUtils.StrToDateDef	Converts a string to a TDateTime value, with error default.
System.SysUtils.StrToDateTime	Converts a string to a TDateTime value.
System.SysUtils.StrToDateTimeDef	Converts a string to a TDateTime value, with error default.
System.SysUtils.StrToTime	Converts a string to a TDateTime value.
System.SysUtils.StrToTimeDef	Converts a string to a TDateTime value, with error default.
System.SysUtils.SystemTimeToDateTime	Converts a system time value into a TDateTime value.
System.SysUtils.TimeStampToDateTime	Converts a TTimeStamp value into the corresponding TDateTime value.
System.SysUtils.TimeStampToMSecs	Converts a TTimeStamp value into an absolute number of milliseconds.
System.SysUtils.TimeToStr	Returns a string that represents a TDateTime value.
System.SysUtils.TryFloatToDateTime	Converts a floating-point value to a TDateTime value.
System.DateUtils.TryJulianDateToDateTime	Converts a Julian date to a TDateTime value.
System.DateUtils.TryModifiedJulianDateToDateTime	Converts a modified Julian date to a TDateTime value.
System.DateUtils.TryRecodeDateTime	Selectively replaces parts of a specified TDateTime value.
System.SysUtils.TryStrToDate	Converts a string to a TDateTime value, with a Boolean success code.
System.SysUtils.TryStrToDateTime	Converts a string to a TDateTime value, with a Boolean success code.
System.SysUtils.TryStrToTime	Converts a string to a TDateTime value, with an error default.
System.DateUtils.UnixToDateTime	Converts a Unix/Linux style date-and-time value to a TDateTime value.

See Also

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