1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- S Y S T E M . O S _ P R I M I T I V E S. T I M E D _ D E L A Y -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 2012-2019, AdaCore -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This is the Posix, Posix2008, and LynxOS version of this procedure. 33 34separate (System.OS_Primitives) 35procedure Timed_Delay 36 (Time : Duration; 37 Mode : Integer) 38is 39 Request : aliased timespec; 40 Remaind : aliased timespec; 41 Rel_Time : Duration; 42 Abs_Time : Duration; 43 Base_Time : constant Duration := Clock; 44 Check_Time : Duration := Base_Time; 45 Time_Chunk : Duration; 46 47 Result : Integer; 48 pragma Unreferenced (Result); 49 50begin 51 if Mode = Relative then 52 Rel_Time := Time; 53 Abs_Time := Time + Check_Time; 54 else 55 Rel_Time := Time - Check_Time; 56 Abs_Time := Time; 57 end if; 58 59 -- To keep a sensible Max_Sensible_Delay on a target whose system 60 -- maximum is less than sensible, we split the delay into manageable 61 -- chunks of time less than or equal to the Max_System_Delay. 62 63 if Rel_Time > 0.0 then 64 Time_Chunk := Rel_Time; 65 loop 66 pragma Warnings (Off, "condition is always *"); 67 if Max_System_Delay < Max_Sensible_Delay and then 68 Time_Chunk > Max_System_Delay 69 then 70 Time_Chunk := Max_System_Delay; 71 end if; 72 pragma Warnings (On); 73 74 Request := To_Timespec (Time_Chunk); 75 Result := nanosleep (Request'Access, Remaind'Access); 76 77 Check_Time := Clock; 78 79 exit when Abs_Time <= Check_Time or else Check_Time < Base_Time; 80 81 Time_Chunk := Abs_Time - Check_Time; 82 end loop; 83 end if; 84end Timed_Delay; 85