1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- S Y S T E M . R A N D O M _ S E E D -- 6-- -- 7-- B o d y -- 8-- -- 9-- Copyright (C) 2011-2020, Free Software Foundation, Inc. -- 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-- Version used on all systems except Ravenscar where Calendar is unavailable 33 34with Ada.Calendar; use Ada.Calendar; 35with Ada.Unchecked_Conversion; 36 37package body System.Random_Seed is 38 39 Y2K : constant Time := 40 Time_Of (Year => 2000, Month => 1, Day => 1, Seconds => 0.0); 41 -- First day of Year 2000, to get a duration 42 43 function To_U64 is 44 new Ada.Unchecked_Conversion (Duration, Interfaces.Unsigned_64); 45 46 -------------- 47 -- Get_Seed -- 48 -------------- 49 50 function Get_Seed return Interfaces.Unsigned_64 is 51 begin 52 return To_U64 (Clock - Y2K); 53 end Get_Seed; 54 55end System.Random_Seed; 56