1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS -- 4-- -- 5-- A D A . C A L E N D A R . D E L A Y S -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 1991-2017, Florida State University -- 10-- Copyright (C) 1995-2018, AdaCore -- 11-- -- 12-- GNAT is free software; you can redistribute it and/or modify it under -- 13-- terms of the GNU General Public License as published by the Free Soft- -- 14-- ware Foundation; either version 3, or (at your option) any later ver- -- 15-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 16-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 17-- or FITNESS FOR A PARTICULAR PURPOSE. -- 18-- -- 19-- As a special exception under Section 7 of GPL version 3, you are granted -- 20-- additional permissions described in the GCC Runtime Library Exception, -- 21-- version 3.1, as published by the Free Software Foundation. -- 22-- -- 23-- You should have received a copy of the GNU General Public License and -- 24-- a copy of the GCC Runtime Library Exception along with this program; -- 25-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 26-- <http://www.gnu.org/licenses/>. -- 27-- -- 28-- GNARL was developed by the GNARL team at Florida State University. -- 29-- Extensive contributions were provided by Ada Core Technologies, Inc. -- 30-- -- 31------------------------------------------------------------------------------ 32 33with System.OS_Primitives; 34with System.Soft_Links; 35 36package body Ada.Calendar.Delays is 37 38 package OSP renames System.OS_Primitives; 39 package SSL renames System.Soft_Links; 40 41 use type SSL.Timed_Delay_Call; 42 43 -- Earlier, System.Time_Operations was used to implement the following 44 -- operations. The idea was to avoid sucking in the tasking packages. This 45 -- did not work. Logically, we can't have it both ways. There is no way to 46 -- implement time delays that will have correct task semantics without 47 -- reference to the tasking run-time system. To achieve this goal, we now 48 -- use soft links. 49 50 ----------------------- 51 -- Local Subprograms -- 52 ----------------------- 53 54 procedure Timed_Delay_NT (Time : Duration; Mode : Integer); 55 -- Timed delay procedure used when no tasking is active 56 57 --------------- 58 -- Delay_For -- 59 --------------- 60 61 procedure Delay_For (D : Duration) is 62 begin 63 SSL.Timed_Delay.all (Duration'Min (D, OSP.Max_Sensible_Delay), 64 OSP.Relative); 65 end Delay_For; 66 67 ----------------- 68 -- Delay_Until -- 69 ----------------- 70 71 procedure Delay_Until (T : Time) is 72 D : constant Duration := To_Duration (T); 73 74 begin 75 SSL.Timed_Delay.all (D, OSP.Absolute_Calendar); 76 end Delay_Until; 77 78 -------------------- 79 -- Timed_Delay_NT -- 80 -------------------- 81 82 procedure Timed_Delay_NT (Time : Duration; Mode : Integer) is 83 begin 84 OSP.Timed_Delay (Time, Mode); 85 end Timed_Delay_NT; 86 87 ----------------- 88 -- To_Duration -- 89 ----------------- 90 91 function To_Duration (T : Time) return Duration is 92 begin 93 -- Since time has multiple representations on different platforms, a 94 -- target independent operation in Ada.Calendar is used to perform 95 -- this conversion. 96 97 return Delay_Operations.To_Duration (T); 98 end To_Duration; 99 100begin 101 -- Set up the Timed_Delay soft link to the non tasking version if it has 102 -- not been already set. If tasking is present, Timed_Delay has already set 103 -- this soft link, or this will be overridden during the elaboration of 104 -- System.Tasking.Initialization 105 106 if SSL.Timed_Delay = null then 107 SSL.Timed_Delay := Timed_Delay_NT'Access; 108 end if; 109 110end Ada.Calendar.Delays; 111