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) 1991-2000 Free Software Foundation, Inc. --
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 a OpenVMS/Alpha 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.
48 with System
.OS_Interface
;
49 -- used for pthread_mutex_t
53 package System
.Task_Primitives
is
55 type Lock
is limited private;
56 -- Should be used for implementation of protected objects.
58 type RTS_Lock
is limited private;
59 -- Should be used inside the runtime system.
60 -- The difference between Lock and the RTS_Lock is that the later
61 -- one serves only as a semaphore so that do not check for
62 -- ceiling violations.
64 type Task_Body_Access
is access procedure;
65 -- Pointer to the task body's entry point (or possibly a wrapper
66 -- declared local to the GNARL).
68 type Private_Data
is limited private;
69 -- Any information that the GNULLI needs maintained on a per-task
70 -- basis. A component of this type is guaranteed to be included
71 -- in the Ada_Task_Control_Block.
75 type Exc_Stack_T
is array (0 .. 8192) of aliased Character;
76 for Exc_Stack_T
'Alignment use Standard
'Maximum_Alignment;
77 type Exc_Stack_Ptr_T
is access all Exc_Stack_T
;
80 L
: aliased System
.OS_Interface
.pthread_mutex_t
;
81 Prio
: Interfaces
.C
.int
;
82 Prio_Save
: Interfaces
.C
.int
;
85 type RTS_Lock
is new System
.OS_Interface
.pthread_mutex_t
;
86 type Private_Data
is record
87 Thread
: aliased System
.OS_Interface
.pthread_t
;
88 pragma Atomic
(Thread
);
89 -- Thread field may be updated by two different threads of control.
90 -- (See, Enter_Task and Create_Task in s-taprop.adb).
91 -- They put the same value (thr_self value). We do not want to
92 -- use lock on those operations and the only thing we have to
93 -- make sure is that they are updated in atomic fashion.
95 CV
: aliased System
.OS_Interface
.pthread_cond_t
;
97 -- protection for all components is lock L
99 Exc_Stack_Ptr
: Exc_Stack_Ptr_T
;
100 -- ??? This needs comments.
102 AST_Pending
: Boolean;
103 -- Used to detect delay and sleep timeouts
107 end System
.Task_Primitives
;