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The following language−defined library packages exist:
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package Ada.Calendar.Time_Zones is
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−− Time zone manipulation:
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type Time_Offset is range −28*60 .. 28*60;
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Unknown_Zone_Error : exception;
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function UTC_Time_Offset (Date : Time := Clock) return Time_Offset;
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end Ada.Calendar.Time_Zones;
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package Ada.Calendar.Arithmetic is
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−− Arithmetic on days:
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type Day_Count is range −366*(1+Year_Number'Last − Year_Number'First) .. 366*(1+Year_Number'Last − Year_Number'First);
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subtype Leap_Seconds_Count is Integer range −2047 .. 2047;
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procedure Difference (Left, Right : in Time; Days : out Day_Count; Seconds : out Duration; Leap_Seconds : out Leap_Seconds_Count);
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function "+" (Left : Time; Right : Day_Count) return Time; function "+" (Left : Day_Count; Right : Time) return Time; function "−" (Left : Time; Right : Day_Count) return Time; function "−" (Left, Right : Time) return Day_Count;
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end Ada.Calendar.Arithmetic;
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with Ada.Calendar.Time_Zones; package Ada.Calendar.Formatting is
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−− Day of the week:
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type Day_Name is (Monday, Tuesday, Wednesday, Thursday, Friday, Saturday, Sunday);
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function Day_of_Week (Date : Time) return Day_Name;
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−− Hours:Minutes:Seconds access:
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subtype Hour_Number is Natural range 0 .. 23; subtype Minute_Number is Natural range 0 .. 59; subtype Second_Number is Natural range 0 .. 59; subtype Second_Duration is Day_Duration range 0.0 .. 1.0;
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function Year (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Year_Number;
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function Month (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Month_Number;
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function Day (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Day_Number;
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function Hour (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Hour_Number;
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function Minute (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Minute_Number;
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function Second (Date : Time) return Second_Number;
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function Sub_Second (Date : Time) return Second_Duration;
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function Seconds_Of (Hour : Hour_Number; Minute : Minute_Number; Second : Second_Number := 0; Sub_Second : Second_Duration := 0.0) return Day_Duration;
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procedure Split (Seconds : in Day_Duration; Hour : out Hour_Number; Minute : out Minute_Number; Second : out Second_Number; Sub_Second : out Second_Duration);
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function Time_Of (Year : Year_Number; Month : Month_Number; Day : Day_Number; Hour : Hour_Number; Minute : Minute_Number; Second : Second_Number; Sub_Second : Second_Duration := 0.0; Leap_Second: Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) return Time;
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function Time_Of (Year : Year_Number; Month : Month_Number; Day : Day_Number; Seconds : Day_Duration := 0.0; Leap_Second: Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) return Time;
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procedure Split (Date : in Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Hour : out Hour_Number; Minute : out Minute_Number; Second : out Second_Number; Sub_Second : out Second_Duration; Time_Zone : in Time_Zones.Time_Offset := 0);
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procedure Split (Date : in Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Hour : out Hour_Number; Minute : out Minute_Number; Second : out Second_Number; Sub_Second : out Second_Duration; Leap_Second: out Boolean; Time_Zone : in Time_Zones.Time_Offset := 0);
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procedure Split (Date : in Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Seconds : out Day_Duration; Leap_Second: out Boolean; Time_Zone : in Time_Zones.Time_Offset := 0);
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−− Simple image and value: function Image (Date : Time; Include_Time_Fraction : Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) return String;
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function Value (Date : String; Time_Zone : Time_Zones.Time_Offset := 0) return Time;
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function Image (Elapsed_Time : Duration; Include_Time_Fraction : Boolean := False) return String;
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function Value (Elapsed_Time : String) return Duration;
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end Ada.Calendar.Formatting;
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Type Time_Offset represents the number of minutes difference between the implementation−defined time zone used by Calendar and another time zone.
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function UTC_Time_Offset (Date : Time := Clock) return Time_Offset;
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Returns, as a number of minutes, the difference between the implementation−defined time zone of Calendar, and UTC time, at the time Date. If the time zone of the Calendar implementation is unknown, then Unknown_Zone_Error is raised.
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procedure Difference (Left, Right : in Time; Days : out Day_Count; Seconds : out Duration; Leap_Seconds : out Leap_Seconds_Count);
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Returns the difference between Left and Right. Days is the number of days of difference, Seconds is the remainder seconds of difference excluding leap seconds, and Leap_Seconds is the number of leap seconds. If Left < Right, then Seconds <= 0.0, Days <= 0, and Leap_Seconds <= 0. Otherwise, all values are nonnegative. The absolute value of Seconds is always less than 86_400.0. For the returned values, if Days = 0, then Seconds + Duration(Leap_Seconds) = Calendar."−−" (Left, Right).
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function "+" (Left : Time; Right : Day_Count) return Time; function "+" (Left : Day_Count; Right : Time) return Time;
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Adds a number of days to a time value. Time_Error is raised if the result is not representable as a value of type Time.
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function "−" (Left : Time; Right : Day_Count) return Time;
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Subtracts a number of days from a time value. Time_Error is raised if the result is not representable as a value of type Time.
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function "−" (Left, Right : Time) return Day_Count;
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Subtracts two time values, and returns the number of days between them. This is the same value that Difference would return in Days.
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function Day_of_Week (Date : Time) return Day_Name;
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Returns the day of the week for Time. This is based on the Year, Month, and Day values of Time.
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function Year (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Year_Number;
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Returns the year for Date, as appropriate for the specified time zone offset.
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function Month (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Month_Number;
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Returns the month for Date, as appropriate for the specified time zone offset.
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function Day (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Day_Number;
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Returns the day number for Date, as appropriate for the specified time zone offset.
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function Hour (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Hour_Number;
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Returns the hour for Date, as appropriate for the specified time zone offset.
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function Minute (Date : Time; Time_Zone : Time_Zones.Time_Offset := 0) return Minute_Number;
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Returns the minute within the hour for Date, as appropriate for the specified time zone offset.
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function Second (Date : Time) return Second_Number;
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Returns the second within the hour and minute for Date.
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function Sub_Second (Date : Time) return Second_Duration;
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Returns the fraction of second for Date (this has the same accuracy as Day_Duration). The value returned is always less than 1.0.
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function Seconds_Of (Hour : Hour_Number; Minute : Minute_Number; Second : Second_Number := 0; Sub_Second : Second_Duration := 0.0) return Day_Duration;
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Returns a Day_Duration value for the combination of the given Hour, Minute, Second, and Sub_Second. This value can be used in Calendar.Time_Of as well as the argument to Calendar."+" and Calendar."−−". If Seconds_Of is called with a Sub_Second value of 1.0, the value returned is equal to the value of Seconds_Of for the next second with a Sub_Second value of 0.0.
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procedure Split (Seconds : in Day_Duration; Hour : out Hour_Number; Minute : out Minute_Number; Second : out Second_Number; Sub_Second : out Second_Duration);
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Splits Seconds into Hour, Minute, Second and Sub_Second in such a way that the resulting values all belong to their respective subtypes. The value returned in the Sub_Second parameter is always less than 1.0.
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function Time_Of (Year : Year_Number; Month : Month_Number; Day : Day_Number; Hour : Hour_Number; Minute : Minute_Number; Second : Second_Number; Sub_Second : Second_Duration := 0.0; Leap_Second: Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) return Time;
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If Leap_Second is False, returns a Time built from the date and time values, relative to the specified time zone offset. If Leap_Second is True, returns the Time that represents the time within the leap second that is one second later than the time specified by the other parameters. Time_Error is raised if the parameters do not form a proper date or time. If Time_Of is called with a Sub_Second value of 1.0, the value returned is equal to the value of Time_Of for the next second with a Sub_Second value of 0.0.
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function Time_Of (Year : Year_Number; Month : Month_Number; Day : Day_Number; Seconds : Day_Duration := 0.0; Leap_Second: Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) return Time;
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If Leap_Second is False, returns a Time built from the date and time values, relative to the specified time zone offset. If Leap_Second is True, returns the Time that represents the time within the leap second that is one second later than the time specified by the other parameters. Time_Error is raised if the parameters do not form a proper date or time. If Time_Of is called with a Seconds value of 86_400.0, the value returned is equal to the value of Time_Of for the next day with a Seconds value of 0.0.
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procedure Split (Date : in Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Hour : out Hour_Number; Minute : out Minute_Number; Second : out Second_Number; Sub_Second : out Second_Duration; Leap_Second: out Boolean; Time_Zone : in Time_Zones.Time_Offset := 0);
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If Date does not represent a time within a leap second, splits Date into its constituent parts (Year, Month, Day, Hour, Minute, Second, Sub_Second), relative to the specified time zone offset, and sets Leap_Second to False. If Date represents a time within a leap second, set the constituent parts to values corresponding to a time one second earlier than that given by Date, relative to the specified time zone offset, and sets Leap_Seconds to True. The value returned in the Sub_Second parameter is always less than 1.0.
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procedure Split (Date : in Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Hour : out Hour_Number; Minute : out Minute_Number; Second : out Second_Number; Sub_Second : out Second_Duration; Time_Zone : in Time_Zones.Time_Offset := 0);
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Splits Date into its constituent parts (Year, Month, Day, Hour, Minute, Second, Sub_Second), relative to the specified time zone offset. The value returned in the Sub_Second parameter is always less than 1.0.
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procedure Split (Date : in Time; Year : out Year_Number; Month : out Month_Number; Day : out Day_Number; Seconds : out Day_Duration; Leap_Second: out Boolean; Time_Zone : in Time_Zones.Time_Offset := 0);
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If Date does not represent a time within a leap second, splits Date into its constituent parts (Year, Month, Day, Seconds), relative to the specified time zone offset, and sets Leap_Second to False. If Date represents a time within a leap second, set the constituent parts to values corresponding to a time one second earlier than that given by Date, relative to the specified time zone offset, and sets Leap_Seconds to True. The value returned in the Seconds parameter is always less than 86_400.0.
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function Image (Date : Time; Include_Time_Fraction : Boolean := False; Time_Zone : Time_Zones.Time_Offset := 0) return String;
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Returns a string form of the Date relative to the given Time_Zone. The format is "Year−Month−Day Hour:Minute:Second", where the Year is a 4−digit value, and all others are 2−digit values, of the functions defined in Calendar and Calendar.Formatting, including a leading zero, if needed. The separators between the values are a minus, another minus, a colon, and a single space between the Day and Hour. If Include_Time_Fraction is True, the integer part of Sub_Seconds*100 is suffixed to the string as a point followed by a 2−digit value.
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function Value (Date : String; Time_Zone : Time_Zones.Time_Offset := 0) return Time;
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Returns a Time value for the image given as Date, relative to the given time zone. Constraint_Error is raised if the string is not formatted as described for Image, or the function cannot interpret the given string as a Time value.
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function Image (Elapsed_Time : Duration; Include_Time_Fraction : Boolean := False) return String;
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Returns a string form of the Elapsed_Time. The format is "Hour:Minute:Second", where all values are 2−digit values, including a leading zero, if needed. The separators between the values are colons. If Include_Time_Fraction is True, the integer part of Sub_Seconds*100 is suffixed to the string as a point followed by a 2−digit value. If Elapsed_Time < 0.0, the result is Image (abs Elapsed_Time, Include_Time_Fraction) prefixed with a minus sign. If abs Elapsed_Time represents 100 hours or more, the result is implementation−defined.
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function Value (Elapsed_Time : String) return Duration;
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Returns a Duration value for the image given as Elapsed_Time. Constraint_Error is raised if the string is not formatted as described for Image, or the function cannot interpret the given string as a Duration value.
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An implementation should support leap seconds if the target system supports them. If leap seconds are not supported, Difference should return zero for Leap_Seconds, Split should return False for Leap_Second, and Time_Of should raise Time_Error if Leap_Second is True.
NOTES
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37 The implementation−defined time zone of package Calendar may, but need not, be the local time zone. UTC_Time_Offset always returns the difference relative to the implementation−defined time zone of package Calendar. If UTC_Time_Offset does not raise Unknown_Zone_Error, UTC time can be safely calculated (within the accuracy of the underlying time−base).
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38 Calling Split on the results of subtracting Duration(UTC_Time_Offset*60) from Clock provides the components (hours, minutes, and so on) of the UTC time. In the United States, for example, UTC_Time_Offset will generally be negative.