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------------------------------------------------------------------------------
--                                                                          --
--                 GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS              --
--                                                                          --
--              S Y S T E M . T A S K I N G . U T I L I T I E S             --
--                                                                          --
--                                  S p e c                                 --
--                                                                          --
--                             $Revision: 1.34 $                            --
--                                                                          --
--             Copyright (C) 1991-1998 Florida State University             --
--                                                                          --
-- GNARL is free software; you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
-- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNARL; see file COPYING.  If not, write --
-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
-- MA 02111-1307, USA.                                                      --
--                                                                          --
-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
-- covered  by the  GNU  General  Public  License.  This exception does not --
-- however invalidate  any other reasons why  the executable file  might be --
-- covered by the  GNU Public License.                                      --
--                                                                          --
-- GNARL was developed by the GNARL team at Florida State University. It is --
-- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
-- State University (http://www.gnat.com).                                  --
--                                                                          --
------------------------------------------------------------------------------

--  This package provides RTS Internal Declarations.
--  These declarations are not part of the GNARLI

with Unchecked_Conversion;

package System.Tasking.Utilities is

   function ATCB_To_Address is new
     Unchecked_Conversion (Task_ID, System.Address);

   ---------------------------------
   -- Task_Stage Related routines --
   ---------------------------------

   procedure Make_Independent;
   --  Move the current task to the outermost level (level 1) of the master
   --  master hierarchy of the environment task. This is one level further
   --  out than normal tasks defined in library-level packages (level 2).
   --  The environment task will wait for level 2 tasks to terminate normally,
   --  then it will abort all the level 1 tasks. See Finalize_Global_Tasks
   --  procedure for more information.
   --
   --  This is a dangerous operation, and should only be used on nested tasks
   --  or tasks that depend on any objects that might be finalized earlier than
   --  the termination of the environment task. It is for internal use by
   --  GNARL, to prevent such internal server tasks from preventing a
   --  partition from terminating.

   Independent_Task_Count : Natural := 0;
   --  Number of independent task. This counter is incremented each time
   --  Make_Independent is called. Note that if a server task terminates,
   --  this counter will not be decremented. Since Make_Independent locks
   --  the environment task (because every independent task depends on it),
   --  this counter is protected by the environment task's lock.

   ------------------------------------
   -- Task Abortion related routines --
   ------------------------------------

   procedure Cancel_Queued_Entry_Calls (T : Task_ID);
   --  Cancel any entry calls queued on target task.
   --  Do not call this while holding any locks.

   procedure Exit_One_ATC_Level (Self_ID : Task_ID);
   pragma Inline (Exit_One_ATC_Level);
   --  Call only with abort deferred and holding lock of Self_ID.
   --  This is a bit of common code for all entry calls.
   --  The effect is to exit one level of ATC nesting.

   procedure Abort_One_Task
     (Self_ID : Task_ID;
      T       : Task_ID);
   --  Similar to Locked_Abort_To_Level (Self_ID, T, 0), but:
   --    (1) caller should be holding no locks
   --    (2) may be called for tasks that have not yet been activated
   --    (3) always aborts whole task

   procedure Abort_Tasks (Tasks : Task_List);
   --  Abort_Tasks is called to initiate abortion, however, the actual
   --  abortion is done by abortee by means of Abort_Handler

   procedure Make_Passive
     (Self_ID : Task_ID;
      Task_Completed : Boolean);
   --  Update counts to indicate current task is either terminated
   --  or accepting on a terminate alternative. Call holding no locks.

end System.Tasking.Utilities;