1------------------------------------------------------------------------------
2--                                                                          --
3--                 GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS              --
4--                                                                          --
5--                 S Y S T E M . T A S K _ P R I M I T I V E S              --
6--                                                                          --
7--                                  S p e c                                 --
8--                                                                          --
9--          Copyright (C) 2001-2002 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.       --
30-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
31--                                                                          --
32------------------------------------------------------------------------------
33
34--  This is a VxWorks version of this package.
35
36pragma Polling (Off);
37--  Turn off polling, we do not want ATC polling to take place during
38--  tasking operations. It causes infinite loops and other problems.
39
40with System.OS_Interface;
41
42package System.Task_Primitives is
43
44   type Lock is limited private;
45   --  Should be used for implementation of protected objects.
46
47   type RTS_Lock is limited private;
48   --  Should be used inside the runtime system.
49   --  The difference between Lock and the RTS_Lock is that the later
50   --  one serves only as a semaphore so that do not check for
51   --  ceiling violations.
52
53   type Task_Body_Access is access procedure;
54   --  Pointer to the task body's entry point (or possibly a wrapper
55   --  declared local to the GNARL).
56
57   type Private_Data is limited private;
58   --  Any information that the GNULLI needs maintained on a per-task
59   --  basis.  A component of this type is guaranteed to be included
60   --  in the Ada_Task_Control_Block.
61
62private
63
64   type Priority_Type is (Prio_None, Prio_Protect, Prio_Inherit);
65
66   type Lock is record
67      Mutex        : System.OS_Interface.SEM_ID;
68      Protocol     : Priority_Type;
69      Prio_Ceiling : System.OS_Interface.int;
70      --  priority ceiling of lock
71   end record;
72
73   type RTS_Lock is new Lock;
74
75   type Private_Data is record
76      Thread : aliased System.OS_Interface.t_id := 0;
77      pragma Atomic (Thread);
78      --  Thread field may be updated by two different threads of control.
79      --  (See, Enter_Task and Create_Task in s-taprop.adb).
80      --  They put the same value (thr_self value). We do not want to
81      --  use lock on those operations and the only thing we have to
82      --  make sure is that they are updated in atomic fashion.
83
84      LWP : aliased System.Address;
85      --  The purpose of this field is to provide a better tasking support on
86      --  gdb. The order of the two first fields (Thread and LWP) is important.
87      --  On targets where lwp is not relevant, this is equivalent to Thread.
88
89      CV : aliased System.OS_Interface.SEM_ID;
90
91      L  : aliased RTS_Lock;
92      --  Protection for all components is lock L
93   end record;
94
95end System.Task_Primitives;
96