1 ------------------------------------------------------------------------------
3 -- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
5 -- S Y S T E M . T A S K _ P R I M I T I V E S --
10 -- Copyright (C) 1991-2001 Florida State University --
12 -- GNARL is free software; you can redistribute it and/or modify it under --
13 -- terms of the GNU General Public License as published by the Free Soft- --
14 -- ware Foundation; either version 2, or (at your option) any later ver- --
15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
16 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
17 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNARL; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
21 -- MA 02111-1307, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNARL was developed by the GNARL team at Florida State University. It is --
31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
32 -- State University (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
36 -- This is an OS/2 version of this package.
38 -- This package provides low-level support for most tasking features.
41 -- Turn off polling, we do not want ATC polling to take place during
42 -- tasking operations. It causes infinite loops and other problems.
44 with Interfaces
.OS2Lib
.Threads
;
45 with Interfaces
.OS2Lib
.Synchronization
;
47 package System
.Task_Primitives
is
51 -- type Lock is limited private;
52 -- Should be used for implementation of protected objects.
54 -- type RTS_Lock is limited private;
55 -- Should be used inside the runtime system.
56 -- The difference between Lock and the RTS_Lock is that the later
57 -- one serves only as a semaphore so that do not check for
58 -- ceiling violations.
60 type Task_Body_Access
is access procedure;
61 -- Pointer to the task body's entry point (or possibly a wrapper
62 -- declared local to the GNARL).
64 -- type Private_Data is limited private;
65 -- Any information that the GNULLI needs maintained on a per-task
66 -- basis. A component of this type is guaranteed to be included
67 -- in the Ada_Task_Control_Block.
72 Mutex
: aliased Interfaces
.OS2Lib
.Synchronization
.HMTX
;
74 Owner_Priority
: Integer;
78 type RTS_Lock
is new Lock
;
80 type Private_Data
is record
81 Thread
: aliased Interfaces
.OS2Lib
.Threads
.TID
;
82 pragma Atomic
(Thread
);
83 -- Thread field may be updated by two different threads of control.
84 -- (See, Enter_Task and Create_Task in s-taprop.adb).
85 -- They put the same value (thr_self value). We do not want to
86 -- use lock on those operations and the only thing we have to
87 -- make sure is that they are updated in atomic fashion.
89 CV
: aliased Interfaces
.OS2Lib
.Synchronization
.HEV
;
92 -- Protection for all components is lock L
94 Current_Priority
: Integer := -1;
95 -- The Current_Priority is the actual priority of a thread.
96 -- This field is needed because it is only possible to set a
97 -- delta priority in OS/2. The only places where this field should
98 -- be set are Set_Priority, Create_Task and Initialize (Environment).
100 Wrapper
: Interfaces
.OS2Lib
.Threads
.PFNTHREAD
;
101 -- This is the original wrapper passed by Operations.Create_Task.
102 -- When installing an exception handler in a thread, the thread
103 -- starts executing the Exception_Wrapper which calls Wrapper
104 -- when the handler has been installed. The handler is removed when
108 end System
.Task_Primitives
;