------------------------------------------------------------------------------
--                                                                          --
--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
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--                   A D A . C A L E N D A R . D E L A Y S                  --
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--             Copyright (C) 1991-1994, Florida State University            --
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------------------------------------------------------------------------------

--  This is the Alpha/VMS version.

with System.OS_Primitives;
--  Used for Max_Sensible_Delay

with System.Soft_Links;
--  Used for Timed_Delay

package body Ada.Calendar.Delays is

   package OSP renames System.OS_Primitives;
   package TSL renames System.Soft_Links;

   use type TSL.Timed_Delay_Call;

   ---------------
   -- Delay_For --
   ---------------

   procedure Delay_For (D : Duration) is
   begin
      TSL.Timed_Delay.all
        (Duration'Min (D, OSP.Max_Sensible_Delay), OSP.Relative);
   end Delay_For;

   -----------------
   -- Delay_Until --
   -----------------

   procedure Delay_Until (T : Time) is
   begin
      TSL.Timed_Delay.all (To_Duration (T), OSP.Absolute_Calendar);
   end Delay_Until;

   -----------------
   -- To_Duration --
   -----------------

   function To_Duration (T : Time) return Duration is
   begin
      return OSP.To_Duration (OSP.OS_Time (T), OSP.Absolute_Calendar);
   end To_Duration;

   --------------------
   -- Timed_Delay_NT --
   --------------------

   procedure Timed_Delay_NT (Time : Duration; Mode : Integer);

   procedure Timed_Delay_NT (Time : Duration; Mode : Integer) is
   begin
      OSP.Timed_Delay (Time, Mode);
   end Timed_Delay_NT;

begin
   --  Set up the Timed_Delay soft link to the non tasking version if it has
   --  not been already set.
   --  If tasking is present, Timed_Delay has already set this soft link, or
   --  this will be overriden during the elaboration of
   --  System.Tasking.Initialization

   if TSL.Timed_Delay = null then
      TSL.Timed_Delay := Timed_Delay_NT'Access;
   end if;
end Ada.Calendar.Delays;