gcc/ada/libgnarl/s-tadeca.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
   4 --                                                                          --
   5 --               SYSTEM.TASKING.ASYNC_DELAYS.ENQUEUE_CALENDAR               --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --          Copyright (C) 1998-2018, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNARL 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 -- GNARL was developed by the GNARL team at Florida State University.       --
  28 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 with Ada.Calendar.Delays;
  33
  34 with System.OS_Constants;
  35 with System.OS_Primitives;
  36 with System.Task_Primitives.Operations;
  37 with System.Tasking.Initialization;
  38
  39 function System.Tasking.Async_Delays.Enqueue_Calendar
  40   (T : Ada.Calendar.Time;
  41    D : Delay_Block_Access) return Boolean
  42 is
  43    use type Ada.Calendar.Time;
  44
  45    package SOSC renames System.OS_Constants;
  46    package STPO renames System.Task_Primitives.Operations;
  47
  48    RT_T : Duration := Ada.Calendar.Delays.To_Duration (T);
  49
  50 begin
  51    if T <= Ada.Calendar.Clock then
  52       D.Timed_Out := True;
  53       System.Task_Primitives.Operations.Yield;
  54       return False;
  55    end if;
  56
  57    --  T is expressed as a duration elapsed since the UNIX epoch, whereas
  58    --  Time_Enqueue expects duration elapsed since the epoch of the Ada real-
  59    --  time clock: compensate if necessary.
  60
  61    --  Comparison "SOSC.CLOCK_RT_Ada = SOSC.CLOCK_REALTIME" is compile
  62    --  time known, so turn warnings off.
  63
  64    pragma Warnings (Off);
  65
  66    if SOSC.CLOCK_RT_Ada /= SOSC.CLOCK_REALTIME then
  67       pragma Warnings (On);
  68
  69       RT_T := RT_T - OS_Primitives.Clock + STPO.Monotonic_Clock;
  70    end if;
  71
  72    System.Tasking.Initialization.Defer_Abort
  73      (System.Task_Primitives.Operations.Self);
  74    Time_Enqueue (RT_T, D);
  75    return True;
  76 end System.Tasking.Async_Delays.Enqueue_Calendar;