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 with System.Tasking;
  35 --  Used for Detect_Blocking
  36 --           Self
  37
  38 with Ada.Exceptions;
  39 --  Used for Raise_Exception
  40
  41 with System.Task_Primitives.Operations;
  42 --  Used for Initialize
  43 --           Finalize
  44 --           Current_State
  45 --           Set_False
  46 --           Set_True
  47 --           Suspend_Until_True
  48
  49 package body Ada.Synchronous_Task_Control is
  50
  51    ----------------
  52    -- Initialize --
  53    ----------------
  54
  55    procedure Initialize (S : in out Suspension_Object) is
  56    begin
  57       System.Task_Primitives.Operations.Initialize (S.SO);
  58    end Initialize;
  59
  60    --------------
  61    -- Finalize --
  62    --------------
  63
  64    procedure Finalize (S : in out Suspension_Object) is
  65    begin
  66       System.Task_Primitives.Operations.Finalize (S.SO);
  67    end Finalize;
  68
  69    -------------------
  70    -- Current_State --
  71    -------------------
  72
  73    function Current_State (S : Suspension_Object) return Boolean is
  74    begin
  75       return System.Task_Primitives.Operations.Current_State (S.SO);
  76    end Current_State;
  77
  78    ---------------
  79    -- Set_False --
  80    ---------------
  81
  82    procedure Set_False (S : in out Suspension_Object) is
  83    begin
  84       System.Task_Primitives.Operations.Set_False (S.SO);
  85    end Set_False;
  86
  87    --------------
  88    -- Set_True --
  89    --------------
  90
  91    procedure Set_True (S : in out Suspension_Object) is
  92    begin
  93       System.Task_Primitives.Operations.Set_True (S.SO);
  94    end Set_True;
  95
  96    ------------------------
  97    -- Suspend_Until_True --
  98    ------------------------
  99
 100    procedure Suspend_Until_True (S : in out Suspension_Object) is
 101    begin
 102       --  This is a potentially blocking (see ARM D.10, par. 10), so that
 103       --  if pragma Detect_Blocking is active then Program_Error must be
 104       --  raised if this operation is called from a protected action.
 105
 106       if System.Tasking.Detect_Blocking
 107         and then System.Tasking.Self.Common.Protected_Action_Nesting > 0
 108       then
 109          Ada.Exceptions.Raise_Exception
 110            (Program_Error'Identity, "potentially blocking operation");
 111       end if;
 112
 113       System.Task_Primitives.Operations.Suspend_Until_True (S.SO);
 114    end Suspend_Until_True;
 115
 116 end Ada.Synchronous_Task_Control;