# Date user defined functions Reference

Below is a complete list of the user defined functions available in AutoIt. Click on a user defined function name for a detailed description.

When using them you need to add a #include <Date.au3>.

User Defined Function | Description
--- | ---
_Date_Time_CompareFileTime | Compares two file times
_Date_Time_DOSDateTimeToArray | Decode a DOS date/time to an array
_Date_Time_DOSDateTimeToFileTime | Converts MS-DOS date and time values to a file time
_Date_Time_DOSDateTimeToStr | Decode a DOS date to a string
_Date_Time_DOSDateToArray | Decode a DOS date to an array
_Date_Time_DOSDateToStr | Decode a DOS date to a string
_Date_Time_DOSTimeToArray | Decode a DOS time to an array
_Date_Time_DOSTimeToStr | Decode a DOS time to a string
_Date_Time_EncodeFileTime | Encodes and returns a $tagFILETIME structure
_Date_Time_EncodeSystemTime | Encodes and returns a $tagSYSTEMTIME structure
_Date_Time_FileTimeToArray | Decode a file time to an array
_Date_Time_FileTimeToDOSDateTime | Converts MS-DOS date and time values to a file time
_Date_Time_FileTimeToLocalFileTime | Converts a file time based on the Coordinated Universal Time to a local file time
_Date_Time_FileTimeToStr | Decode a file time to a date/time string
_Date_Time_FileTimeToSystemTime | Converts a file time to system time format
_Date_Time_GetFileTime | Retrieves the date and time that a file was created, accessed and modified
_Date_Time_GetLocalTime | Retrieves the current local date and time
_Date_Time_GetSystemTime | Retrieves the current system date and time expressed in UTC
_Date_Time_GetSystemTimeAdjustment | Determines whether the system is applying periodic time adjustments
_Date_Time_GetSystemTimeAsFileTime | Retrieves the current system date and time expressed in UTC
_Date_Time_GetSystemTimes | Retrieves system timing information
_Date_Time_GetTickCount | Retrieves the number of milliseconds that have elapsed since Windows was started
_Date_Time_GetTimeZoneInformation | Retrieves the current time zone settings
_Date_Time_LocalFileTimeToFileTime | Converts a local file time to a file time based on UTC
_Date_Time_SetFileTime | Sets the date and time that a file was created, accessed and modified
_Date_Time_SetLocalTime | Sets the current local date and time
_Date_Time_SetSystemTime | Sets the current system time and date, expressed in UTC
_Date_Time_SetSystemTimeAdjustment | Enables or disables periodic time adjustments to the system's time of day clock
_Date_Time_SetTimeZoneInformation | Sets the current time zone settings
_Date_Time_SystemTimeToArray | Decode a system time to an array
_Date_Time_SystemTimeToDateStr | Decode a system time to a date string
_Date_Time_SystemTimeToDateTimeStr | Decode a system time to a date/time string
_Date_Time_SystemTimeToFileTime | Converts a system time to file time format
_Date_Time_SystemTimeToTimeStr | Decode a system time to a time string
_Date_Time_SystemTimeToTzSpecificLocalTime | Converts a UTC time to a specified time zone's corresponding local time
_Date_Time_TzSpecificLocalTimeToSystemTime | Converts a local time to a time in UTC
_DateAdd | Calculates a new date/time by adding/subtracting a specified number of time intervals from an initial date/time
_DateDayOfWeek | Returns the name of the weekday, based on the specified day
_DateDaysInMonth | Returns the number of days in a month, based on the specified month and year
_DateDiff | Returns the difference between 2 dates, expressed in the type requested
_DateIsLeapYear | Checks a given year to see if it is a leap year
_DateIsValid | Checks the given date to determine if it is a valid date
_DateTimeFormat | Returns the date in the PC's regional settings format
_DateTimeSplit | Split a string containing Date and Time into two separate Arrays
_DateToDayOfWeek | Returns the weekday number for a given date
_DateToDayOfWeekISO | Returns the ISO weekday number for a given date
_DateToDayValue | Returns the day number since noon 4713 BC January 1 for a given Gregorian date
_DateToMonth | Returns the name of the month, based on the specified month
_DayValueToDate | Add the given days since noon 4713 BC January 1 and returns the Gregorian date
_Now | Returns the current Date and Time in PC's format
_NowCalc | Returns the current Date and Time in format YYYY/MM/DD HH:MM:SS for use in date calculations
_NowCalcDate | Returns the current Date in format YYYY/MM/DD
_NowDate | Returns the current Date in the Pc's format
_NowTime | Returns the current Time in the requested format
_SetDate | Sets the current date of the system
_SetTime | Sets the current time of the system
_TicksToTime | Converts the specified tick amount to hours, minutes and seconds
_TimeToTicks | Converts the specified hours, minutes, and seconds to ticks
_WeekNumberISO | Calculate the weeknumber of a given date