+2012-01-23 Robert Dewar <dewar@adacore.com>
+
+ * a-catizo.ads, a-calend.adb, a-calend.ads, par-ch13.adb: Minor
+ reformatting.
+
2012-01-23 Ed Schonberg <schonberg@adacore.com>
* sem_ch6.adb (Analyze_Subprogram_Declaration): Do not set the
------------------------------------------------------------------------------
with Ada.Unchecked_Conversion;
+
with Interfaces.C;
+
with System.OS_Primitives;
package body Ada.Calendar is
-- This routine acts as an Ada wrapper around __gnat_localtime_tzoff which
-- in turn utilizes various OS-dependent mechanisms to calculate the time
-- zone offset of a date. Formal parameter Date represents an arbitrary
- -- time stamp, either in the past, now, or in the future. If flag
+ -- time stamp, either in the past, now, or in the future. If the flag
-- Is_Historic is set, this routine would try to calculate to the best of
-- the OS's abilities the time zone offset that was or will be in effect
-- on Date. If the flag is set to False, the routine returns the current
-- time zone with Date effectively set to Clock.
+ --
-- NOTE: Targets which support localtime_r will aways return a historic
-- time zone even if flag Is_Historic is set to False because this is how
-- localtime_r operates.
Unix_Min : constant Time_Rep :=
Ada_Low + Time_Rep (17 * 366 + 52 * 365) * Nanos_In_Day;
- -- The Unix upper time bound expressed as nonoseconds since the start of
+ -- The Unix upper time bound expressed as nanoseconds since the start of
-- Ada time in UTC.
Unix_Max : constant Time_Rep :=
-- of year - 4 to year + 4. Internally, routines Split and Time_Of add or
-- subtract a "fake" February 29 to facilitate the arithmetic involved.
+ ------------------------------------
+ -- Time zones and UTC_Time_Offset --
+ ------------------------------------
+
+ -- The implementation-defined time zone of Ada.Calendar routines is the
+ -- local time zone. The term "local time zone" can be interpreted in two
+ -- different ways - either the offset from UTC of the "now" or the offset
+ -- from UTC of some input date.
+
+ -- For efficency reasons, Split and Time_Of take the first approach. Since
+ -- the Ada Reference Manual does not mandate that Split and Time_Of should
+ -- be concious of historic time zones, this interpretation is acceptable
+ -- and efficent in terms of performance. Split and Time_Of localize their
+ -- respective input regardless of whether it represent a past or a future
+ -- date.
+
+ -- UTC_Time_Offset on the other hand must be knowledgeable of historic time
+ -- zones. To achieve this, the implementation relies on various operating
+ -- system routines. Note that not all operating systems support time zones.
+ -- UTC_Time_Offset calculates the offset from UTC as it occurred or will
+ -- occur on the input date relative to the local time zone. Example:
+
+ -- Date Offset Reason
+ -- 2012-01-11 -300
+ -- 2011-03-12 -300
+ -- 2011-03-14 -240 Daylight savings is in effect
+
+ -- Local declarations
+
-- The underlying type of Time has been chosen to be a 64 bit signed
-- integer number since it allows for easier processing of sub seconds
-- and arithmetic.
package Time_Zones_Operations is
function UTC_Time_Offset (Date : Time) return Long_Integer;
- -- Return (in seconds), the difference between the local time zone and
+ -- Return (in seconds) the difference between the local time zone and
-- UTC time at a specific historic date.
end Time_Zones_Operations;
-- --
-- S p e c --
-- --
--- Copyright (C) 2005-2012, Free Software Foundation, Inc. --
--- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. In accordance with the copyright of that document, you can freely --
-- copy and modify this specification, provided that if you redistribute a --
if Token = Tok_Comma
or else Token = Tok_Semicolon
-
then
- -- or else (not Semicolon and then Token /= Tok_Arrow)
if Aspect_Argument (A_Id) /= Optional then
Error_Msg_Node_1 := Identifier (Aspect);
Error_Msg_AP ("aspect& requires an aspect definition");
OK := False;
-
end if;
elsif not Semicolon and then Token /= Tok_Arrow then
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