------------------------------------------------------------------------------ -- -- -- GNAT 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 -- -- -- -- Copyright (C) 1991-2005 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, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, 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. -- -- Extensive contributions were provided by Ada Core Technologies, Inc. -- -- -- ------------------------------------------------------------------------------ -- This is a OpenVMS/Alpha version of this package -- This package provides low-level support for most tasking features 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 pragma Preelaborate; 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 Suspension_Object is limited private; -- Should be used for the implementation of Ada.Synchronous_Task_Control 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 Exc_Stack_T is array (0 .. 8192) of aliased Character; for Exc_Stack_T'Alignment use Standard'Maximum_Alignment; type Exc_Stack_Ptr_T is access all Exc_Stack_T; type Lock is record L : aliased System.OS_Interface.pthread_mutex_t; Prio : Interfaces.C.int; Prio_Save : Interfaces.C.int; end record; type RTS_Lock is new System.OS_Interface.pthread_mutex_t; type Suspension_Object is record State : Boolean; pragma Atomic (State); -- Boolean that indicates whether the object is open. This field is -- marked Atomic to ensure that we can read its value without locking -- the access to the Suspension_Object. Waiting : Boolean; -- Flag showing if there is a task already suspended on this object L : aliased System.OS_Interface.pthread_mutex_t; -- Protection for ensuring mutual exclusion on the Suspension_Object CV : aliased System.OS_Interface.pthread_cond_t; -- Condition variable used to queue threads until ondition is signaled end record; type Private_Data is record Thread : aliased System.OS_Interface.pthread_t; 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. CV : aliased System.OS_Interface.pthread_cond_t; L : aliased RTS_Lock; -- Protection for all components is lock L Exc_Stack_Ptr : Exc_Stack_Ptr_T; -- ??? This needs comments AST_Pending : Boolean; -- Used to detect delay and sleep timeouts end record; end System.Task_Primitives;