File : s-taspri.ads
------------------------------------------------------------------------------
-- --
-- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . T A S K _ P R I M I T I V E S --
-- --
-- S p e c --
-- --
-- $Revision: 1.10 $ --
-- --
-- Copyright (C) 1991-1998 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- --
-- 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 is a NT (native) version of this package.
pragma Polling (Off);
-- Turn off polling, we do not want ATC polling to take place during
-- tasking operations. It causes infinite loops and other problems.
with Interfaces.C;
-- used for int
-- size_t
with System.OS_Interface;
-- used for pthread_mutex_t
-- pthread_cond_t
-- pthread_t
package System.Task_Primitives is
type Lock is limited private;
-- Should be used for implementation of protected objects.
type RTS_Lock is limited private;
-- Should be used inside the runtime system.
-- The difference between Lock and the RTS_Lock is that the later
-- one serves only as a semaphore so that do not check for
-- ceiling violations.
type Task_Body_Access is access procedure;
-- Pointer to the task body's entry point (or possibly a wrapper
-- declared local to the GNARL).
type Private_Data is limited private;
-- Any information that the GNULLI needs maintained on a per-task
-- basis. A component of this type is guaranteed to be included
-- in the Ada_Task_Control_Block.
private
type Lock is record
Mutex : aliased System.OS_Interface.CRITICAL_SECTION;
Priority : Integer;
Owner_Priority : Integer;
end record;
type Condition_Variable is new System.OS_Interface.HANDLE;
type RTS_Lock is new System.OS_Interface.CRITICAL_SECTION;
type Private_Data is record
Thread : aliased System.OS_Interface.HANDLE;
pragma Atomic (Thread);
-- Thread field may be updated by two different threads of control.
-- (See, Enter_Task and Create_Task in s-taprop.adb).
-- They put the same value (thr_self value). We do not want to
-- use lock on those operations and the only thing we have to
-- make sure is that they are updated in atomic fashion.
Thread_Id : aliased System.OS_Interface.DWORD;
-- The purpose of this field is to provide a better
-- tasking support on gdb. The order of the two first fields (Thread
-- and LWP) is important.
CV : aliased Condition_Variable;
-- Condition Variable used to implement Sleep/Wakeup
L : aliased RTS_Lock;
-- Protection for all components is lock L
Current_Priority : Interfaces.C.int := 0;
-- Active priority, except that the effects of protected object
-- priority ceilings are not reflected. This only reflects explicit
-- priority changes and priority inherited through task activation
-- and rendezvous.
--
-- Ada 95 notes: In Ada 95, this field will be transferred to the
-- Priority field of an Entry_Calls component when an entry call
-- is initiated. The Priority of the Entry_Calls component will not
-- change for the duration of the call. The accepting task can
-- use it to boost its own priority without fear of its changing in
-- the meantime.
--
-- This can safely be used in the priority ordering
-- of entry queues. Once a call is queued, its priority does not
-- change.
--
-- Since an entry call cannot be made while executing
-- a protected action, the priority of a task will never reflect a
-- priority ceiling change at the point of an entry call.
--
-- Protection: Only written by Self, and only accessed when Acceptor
-- accepts an entry or when Created activates, at which points Self is
-- suspended.
Stack_Size : Interfaces.C.size_t;
-- Requested stack size.
-- Protection: Only used by Self.
Aborted : Boolean := False;
-- Used to abort tasks asynchronously
end record;
end System.Task_Primitives;