------------------------------------------------------------------------------
-- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
+-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K I N G . I N I T I A L I Z A T I O N --
-- --
-- S p e c --
-- --
--- Copyright (C) 1992-2004, Free Software Foundation, Inc. --
+-- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
-- --
-- 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- --
+-- ware Foundation; either version 3, or (at your option) any later ver- --
+-- sion. GNAT 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. --
+-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
--- 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. --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception, --
+-- version 3.1, as published by the Free Software Foundation. --
+-- --
+-- You should have received a copy of the GNU General Public License and --
+-- a copy of the GCC Runtime Library Exception along with this program; --
+-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
+-- <http://www.gnu.org/licenses/>. --
-- --
-- GNARL was developed by the GNARL team at Florida State University. --
-- Extensive contributions were provided by Ada Core Technologies, Inc. --
package System.Tasking.Initialization is
procedure Remove_From_All_Tasks_List (T : Task_Id);
- -- Remove T from All_Tasks_List.
- -- Call this function with RTS_Lock taken.
+ -- Remove T from All_Tasks_List. Call this function with RTS_Lock taken
---------------------------------
-- Tasking-Specific Soft Links --
-- These permit us to leave out certain portions of the tasking
-- run-time system if they are not used. They are only used internally
-- by the tasking run-time system.
- -- So far, the only example is support for Ada.Task_Attributes.
+
+ -- So far, the only example is support for Ada.Task_Attributes
type Proc_T is access procedure (T : Task_Id);
procedure Initialize_Attributes (T : Task_Id);
Finalize_Attributes_Link : Proc_T := Finalize_Attributes'Access;
- -- should be called with abortion deferred and T.L write-locked
+ -- should be called with abort deferred and T.L write-locked
Initialize_Attributes_Link : Proc_T := Initialize_Attributes'Access;
- -- should be called with abortion deferred, but holding no locks
+ -- should be called with abort deferred, but holding no locks
-------------------------
-- Abort Defer/Undefer --
-- in the calling task until a matching Undefer_Abort call is executed.
-- Undefer_Abort DOES MORE than just undo the effects of one call to
- -- Defer_Abort. It is the universal "polling point" for deferred
+ -- Defer_Abort. It is the universal "polling point" for deferred
-- processing, including the following:
-- 1) base priority changes
-- 2) abort/ATC
- -- Abort deferral MAY be nested (Self_ID.Deferral_Level is a count),
- -- but to avoid waste and undetected errors, it generally SHOULD NOT
- -- be nested. The symptom of over-deferring abort is that an exception
- -- may fail to be raised, or an abort may fail to take place.
+ -- Abort deferral MAY be nested (Self_ID.Deferral_Level is a count), but
+ -- to avoid waste and undetected errors, it generally SHOULD NOT be
+ -- nested. The symptom of over-deferring abort is that an exception may
+ -- fail to be raised, or an abort may fail to take place.
- -- Therefore, there are two sets of the inlinable defer/undefer
- -- routines, which are the ones to be used inside GNARL.
- -- One set allows nesting. The other does not. People who
- -- maintain the GNARL should try to avoid using the nested versions,
- -- or at least look very critically at the places where they are
- -- used.
+ -- Therefore, there are two sets of the inlineable defer/undefer routines,
+ -- which are the ones to be used inside GNARL. One set allows nesting. The
+ -- other does not. People who maintain the GNARL should try to avoid using
+ -- the nested versions, or at least look very critically at the places
+ -- where they are used.
- -- In general, any GNARL call that is potentially blocking, or
- -- whose semantics require that it sometimes raise an exception,
- -- or that is required to be an abort completion point, must be
- -- made with abort Deferral_Level = 1.
+ -- In general, any GNARL call that is potentially blocking, or whose
+ -- semantics require that it sometimes raise an exception, or that is
+ -- required to be an abort completion point, must be made with abort
+ -- Deferral_Level = 1.
- -- In general, non-blocking GNARL calls, which may be made from inside
- -- a protected action, are likely to need to allow nested abort
- -- deferral.
+ -- In general, non-blocking GNARL calls, which may be made from inside a
+ -- protected action, are likely to need to allow nested abort deferral.
-- With some critical exceptions (which are supposed to be documented),
-- internal calls to the tasking runtime system assume abort is already
-- deferred, and do not modify the deferral level.
- -- There is also a set of non-linable defer/undefer routines,
- -- for direct call from the compiler. These are not in-lineable
- -- because they may need to be called via pointers ("soft links").
- -- For the sake of efficiency, the version with Self_ID as parameter
- -- should used wherever possible. These are all nestable.
+ -- There is also a set of non-inlineable defer/undefer routines, for direct
+ -- call from the compiler. These are not inlineable because they may need
+ -- to be called via pointers ("soft links"). For the sake of efficiency,
+ -- the version with Self_ID as parameter should used wherever possible.
+ -- These are all nestable.
-- Non-nestable inline versions
procedure Undefer_Abort_Nestable (Self_ID : Task_Id);
pragma Inline (Undefer_Abort_Nestable);
- -- NON-INLINE versions without Self_ID for code generated by the
- -- expander and for soft links
-
- procedure Defer_Abortion;
- procedure Undefer_Abortion;
-
- -- ?????
- -- Try to phase out all uses of the above versions.
-
procedure Do_Pending_Action (Self_ID : Task_Id);
- -- Only call with no locks, and when Self_ID.Pending_Action = True
- -- Perform necessary pending actions (e.g. abortion, priority change).
- -- This procedure is usually called when needed as a result of
- -- calling Undefer_Abort, although in the case of e.g. No_Abort
- -- restriction, it can be necessary to force execution of pending
- -- actions.
+ -- Only call with no locks, and when Self_ID.Pending_Action = True Perform
+ -- necessary pending actions (e.g. abort, priority change). This procedure
+ -- is usually called when needed as a result of calling Undefer_Abort,
+ -- although in the case of e.g. No_Abort restriction, it can be necessary
+ -- to force execution of pending actions.
function Check_Abort_Status return Integer;
-- Returns Boolean'Pos (True) iff abort signal should raise
--------------------------
procedure Change_Base_Priority (T : Task_Id);
- -- Change the base priority of T.
- -- Has to be called with the affected task's ATCB write-locked.
- -- May temporariliy release the lock.
-
- procedure Poll_Base_Priority_Change (Self_ID : Task_Id);
- -- Has to be called with Self_ID's ATCB write-locked.
- -- May temporariliy release the lock.
- pragma Inline (Poll_Base_Priority_Change);
+ -- Change the base priority of T. Has to be called with the affected
+ -- task's ATCB write-locked. May temporarily release the lock.
----------------------
-- Task Lock/Unlock --
-- within the GNARL.
procedure Final_Task_Unlock (Self_ID : Task_Id);
- -- This version is only for use in Terminate_Task, when the task
- -- is relinquishing further rights to its own ATCB.
- -- There is a very interesting potential race condition there, where
- -- the old task may run concurrently with a new task that is allocated
- -- the old tasks (now reused) ATCB. The critical thing here is to
- -- not make any reference to the ATCB after the lock is released.
- -- See also comments on Terminate_Task and Unlock.
+ -- This version is only for use in Terminate_Task, when the task is
+ -- relinquishing further rights to its own ATCB. There is a very
+ -- interesting potential race condition there, where the old task may run
+ -- concurrently with a new task that is allocated the old tasks (now
+ -- reused) ATCB. The critical thing here is to not make any reference to
+ -- the ATCB after the lock is released. See also comments on
+ -- Terminate_Task and Unlock.
procedure Wakeup_Entry_Caller
(Self_ID : Task_Id;
Entry_Call : Entry_Call_Link;
New_State : Entry_Call_State);
pragma Inline (Wakeup_Entry_Caller);
- -- This is called at the end of service of an entry call,
- -- to abort the caller if he is in an abortable part, and
- -- to wake up the caller if he is on Entry_Caller_Sleep.
- -- Call it holding the lock of Entry_Call.Self.
+ -- This is called at the end of service of an entry call, to abort the
+ -- caller if he is in an abortable part, and to wake up the caller if he
+ -- is on Entry_Caller_Sleep. Call it holding the lock of Entry_Call.Self.
--
-- Timed_Call or Simple_Call:
- -- The caller is waiting on Entry_Caller_Sleep, in
- -- Wait_For_Completion, or Wait_For_Completion_With_Timeout.
+ -- The caller is waiting on Entry_Caller_Sleep, in Wait_For_Completion,
+ -- or Wait_For_Completion_With_Timeout.
--
-- Conditional_Call:
-- The caller might be in Wait_For_Completion,
- -- waiting for a rendezvous (possibly requeued without abort)
- -- to complete.
+ -- waiting for a rendezvous (possibly requeued without abort) to
+ -- complete.
--
-- Asynchronous_Call:
- -- The caller may be executing in the abortable part o
- -- an async. select, or on a time delay,
- -- if Entry_Call.State >= Was_Abortable.
+ -- The caller may be executing in the abortable part an async. select,
+ -- or on a time delay, if Entry_Call.State >= Was_Abortable.
procedure Locked_Abort_To_Level
(Self_ID : Task_Id;
T : Task_Id;
L : ATC_Level);
pragma Inline (Locked_Abort_To_Level);
- -- Abort a task to a specified ATC level.
- -- Call this only with T locked.
+ -- Abort a task to a specified ATC level. Call this only with T locked
end System.Tasking.Initialization;
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