gcc/ada/s-tasuti.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                 GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS              --
   4 --                                                                          --
   5 --              S Y S T E M . T A S K I N G . U T I L I T I E S             --
   6 --                                                                          --
   7 --                                  S p e c                                 --
   8 --                                                                          --
   9 --         Copyright (C) 1992-2002, 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,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, 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. It is --
  30 -- now maintained by Ada Core Technologies, Inc. (http://www.gnat.com).     --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This package provides RTS Internal Declarations.
  35 --  These declarations are not part of the GNARLI
  36
  37 with Unchecked_Conversion;
  38
  39 package System.Tasking.Utilities is
  40
  41    function ATCB_To_Address is new
  42      Unchecked_Conversion (Task_ID, System.Address);
  43
  44    ---------------------------------
  45    -- Task_Stage Related routines --
  46    ---------------------------------
  47
  48    procedure Make_Independent;
  49    --  Move the current task to the outermost level (level 2) of the master
  50    --  hierarchy of the environment task. That is one level further out
  51    --  than normal tasks defined in library-level packages (level 3). The
  52    --  environment task will wait for level 3 tasks to terminate normally,
  53    --  then it will abort all the level 2 tasks. See Finalize_Global_Tasks
  54    --  procedure for more information.
  55    --
  56    --  This is a dangerous operation, and should only be used on nested tasks
  57    --  or tasks that depend on any objects that might be finalized earlier than
  58    --  the termination of the environment task. It is for internal use by the
  59    --  GNARL, to prevent such internal server tasks from preventing a partition
  60    --  from terminating.
  61    --
  62    --  Also note that the run time assumes that the parent of an independent
  63    --  task is the environment task. If this is not the case, Make_Independent
  64    --  will change the task's parent. This assumption is particularly
  65    --  important for master level completion and for the computation of
  66    --  Independent_Task_Count.
  67
  68    Independent_Task_Count : Natural := 0;
  69    --  Number of independent task. This counter is incremented each time
  70    --  Make_Independent is called. Note that if a server task terminates,
  71    --  this counter will not be decremented. Since Make_Independent locks
  72    --  the environment task (because every independent task depends on it),
  73    --  this counter is protected by the environment task's lock.
  74
  75    ------------------------------------
  76    -- Task Abortion related routines --
  77    ------------------------------------
  78
  79    procedure Cancel_Queued_Entry_Calls (T : Task_ID);
  80    --  Cancel any entry calls queued on target task.
  81    --  Call this while holding T's lock (or RTS_Lock in Single_Lock mode).
  82
  83    procedure Exit_One_ATC_Level (Self_ID : Task_ID);
  84    pragma Inline (Exit_One_ATC_Level);
  85    --  Call only with abort deferred and holding lock of Self_ID.
  86    --  This is a bit of common code for all entry calls.
  87    --  The effect is to exit one level of ATC nesting.
  88
  89    procedure Abort_One_Task (Self_ID : Task_ID; T : Task_ID);
  90    --  Similar to Locked_Abort_To_Level (Self_ID, T, 0), but:
  91    --    (1) caller should be holding no locks
  92    --    (2) may be called for tasks that have not yet been activated
  93    --    (3) always aborts whole task
  94
  95    procedure Abort_Tasks (Tasks : Task_List);
  96    --  Abort_Tasks is called to initiate abortion, however, the actual
  97    --  abortion is done by abortee by means of Abort_Handler
  98
  99    procedure Make_Passive (Self_ID : Task_ID; Task_Completed : Boolean);
 100    --  Update counts to indicate current task is either terminated
 101    --  or accepting on a terminate alternative.
 102    --  Call holding no locks except Global_Task_Lock when calling from
 103    --  Terminate_Task, and RTS_Lock when Single_Lock is True.
 104
 105 end System.Tasking.Utilities;