gcc/ada/a-sytaco.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --         A D A . S Y N C H R O N O U S _ T A S K _ C O N T R O L          --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2005 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 2,  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.  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 GNAT;  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 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 pragma Warnings (Off);
  35 --  Allow withing of non-Preelaborated units in Ada 2005 mode where this
  36 --  package will be categorized as Preelaborate. See AI-362 for details.
  37 --  It is safe in the context of the run-time to violate the rules!
  38
  39 with System.Tasking;
  40 --  Used for Detect_Blocking
  41 --           Self
  42
  43 with Ada.Exceptions;
  44 --  Used for Raise_Exception
  45
  46 with System.Task_Primitives.Operations;
  47 --  Used for Initialize
  48 --           Finalize
  49 --           Current_State
  50 --           Set_False
  51 --           Set_True
  52 --           Suspend_Until_True
  53
  54 pragma Warnings (On);
  55
  56 package body Ada.Synchronous_Task_Control is
  57
  58    ----------------
  59    -- Initialize --
  60    ----------------
  61
  62    procedure Initialize (S : in out Suspension_Object) is
  63    begin
  64       System.Task_Primitives.Operations.Initialize (S.SO);
  65    end Initialize;
  66
  67    --------------
  68    -- Finalize --
  69    --------------
  70
  71    procedure Finalize (S : in out Suspension_Object) is
  72    begin
  73       System.Task_Primitives.Operations.Finalize (S.SO);
  74    end Finalize;
  75
  76    -------------------
  77    -- Current_State --
  78    -------------------
  79
  80    function Current_State (S : Suspension_Object) return Boolean is
  81    begin
  82       return System.Task_Primitives.Operations.Current_State (S.SO);
  83    end Current_State;
  84
  85    ---------------
  86    -- Set_False --
  87    ---------------
  88
  89    procedure Set_False (S : in out Suspension_Object) is
  90    begin
  91       System.Task_Primitives.Operations.Set_False (S.SO);
  92    end Set_False;
  93
  94    --------------
  95    -- Set_True --
  96    --------------
  97
  98    procedure Set_True (S : in out Suspension_Object) is
  99    begin
 100       System.Task_Primitives.Operations.Set_True (S.SO);
 101    end Set_True;
 102
 103    ------------------------
 104    -- Suspend_Until_True --
 105    ------------------------
 106
 107    procedure Suspend_Until_True (S : in out Suspension_Object) is
 108    begin
 109       --  This is a potentially blocking (see ARM D.10, par. 10), so that
 110       --  if pragma Detect_Blocking is active then Program_Error must be
 111       --  raised if this operation is called from a protected action.
 112
 113       if System.Tasking.Detect_Blocking
 114         and then System.Tasking.Self.Common.Protected_Action_Nesting > 0
 115       then
 116          Ada.Exceptions.Raise_Exception
 117            (Program_Error'Identity, "potentially blocking operation");
 118       end if;
 119
 120       System.Task_Primitives.Operations.Suspend_Until_True (S.SO);
 121    end Suspend_Until_True;
 122
 123 end Ada.Synchronous_Task_Control;