gcc/ada/a-retide.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                  GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                --
   4 --                                                                          --
   5 --                   A D A . R E A L _ T I M E . D E L A Y S                --
   6 --                                                                          --
   7 --                                  B o d y                                 --
   8 --                                                                          --
   9 --         Copyright (C) 1992-2006, 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 2,  or (at your option) any later ver- --
  14 -- sion. GNARL 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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies, Inc.     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 with Ada.Exceptions;
  35 --  Used for Raise_Exception
  36
  37 with System.Tasking;
  38 --  Used for Task_Id
  39 --           Initialize
  40
  41 with System.Task_Primitives.Operations;
  42 --  Used for Timed_Delay
  43 --           Self
  44
  45 package body Ada.Real_Time.Delays is
  46
  47    package STPO renames System.Task_Primitives.Operations;
  48
  49    ----------------
  50    -- Local Data --
  51    ----------------
  52
  53    Absolute_RT : constant := 2;
  54
  55    -----------------
  56    -- Delay_Until --
  57    -----------------
  58
  59    procedure Delay_Until (T : Time) is
  60       Self_Id : constant System.Tasking.Task_Id := STPO.Self;
  61
  62    begin
  63       --  If pragma Detect_Blocking is active, Program_Error must be
  64       --  raised if this potentially blocking operation is called from a
  65       --  protected action.
  66
  67       if System.Tasking.Detect_Blocking
  68         and then Self_Id.Common.Protected_Action_Nesting > 0
  69       then
  70          Ada.Exceptions.Raise_Exception
  71            (Program_Error'Identity, "potentially blocking operation");
  72       else
  73          STPO.Timed_Delay (Self_Id, To_Duration (T), Absolute_RT);
  74       end if;
  75    end Delay_Until;
  76
  77    -----------------
  78    -- To_Duration --
  79    -----------------
  80
  81    function To_Duration (T : Time) return Duration is
  82    begin
  83       return To_Duration (Time_Span (T));
  84    end To_Duration;
  85
  86 begin
  87    --  Ensure that the tasking run time is initialized when using delay
  88    --  operations. The initialization routine has the required machinery to
  89    --  prevent multiple calls to Initialize.
  90
  91    System.Tasking.Initialize;
  92 end Ada.Real_Time.Delays;