1 ------------------------------------------------------------------------------
3 -- GNAT 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 --
9 -- Copyright (C) 1991-2008, Free Software Foundation, Inc. --
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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
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. --
29 -- GNARL was developed by the GNARL team at Florida State University. --
30 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
32 ------------------------------------------------------------------------------
34 -- This is a NT (native) version of this package
37 -- Turn off polling, we do not want ATC polling to take place during tasking
38 -- operations. It causes infinite loops and other problems.
40 with System.OS_Interface;
42 package System.Task_Primitives is
45 type Lock is limited private;
46 -- Should be used for implementation of protected objects
48 type RTS_Lock is limited private;
49 -- Should be used inside the runtime system. The difference between Lock
50 -- and the RTS_Lock is that the later one serves only as a semaphore so
51 -- that do not check for ceiling violations.
53 type Suspension_Object is limited private;
54 -- Should be used for the implementation of Ada.Synchronous_Task_Control
56 type Task_Body_Access is access procedure;
57 -- Pointer to the task body's entry point (or possibly a wrapper
58 -- declared local to the GNARL).
60 type Private_Data is limited private;
61 -- Any information that the GNULLI needs maintained on a per-task basis.
62 -- A component of this type is guaranteed to be included in the
63 -- Ada_Task_Control_Block.
68 Mutex : aliased System.OS_Interface.CRITICAL_SECTION;
70 Owner_Priority : Integer;
73 type Condition_Variable is new System.OS_Interface.HANDLE;
75 type RTS_Lock is new System.OS_Interface.CRITICAL_SECTION;
77 type Suspension_Object is record
79 pragma Atomic (State);
80 -- Boolean that indicates whether the object is open. This field is
81 -- marked Atomic to ensure that we can read its value without locking
82 -- the access to the Suspension_Object.
85 -- Flag showing if there is a task already suspended on this object
87 L : aliased System.OS_Interface.CRITICAL_SECTION;
88 -- Protection for ensuring mutual exclusion on the Suspension_Object
90 CV : aliased System.OS_Interface.HANDLE;
91 -- Condition variable used to queue threads until condition is signaled
94 type Private_Data is record
95 Thread : aliased System.OS_Interface.HANDLE;
96 pragma Atomic (Thread);
97 -- Thread field may be updated by two different threads of control.
98 -- (See, Enter_Task and Create_Task in s-taprop.adb).
99 -- They put the same value (thr_self value). We do not want to
100 -- use lock on those operations and the only thing we have to
101 -- make sure is that they are updated in atomic fashion.
103 Thread_Id : aliased System.OS_Interface.DWORD;
104 -- Used to provide a better tasking support in gdb
106 CV : aliased Condition_Variable;
107 -- Condition Variable used to implement Sleep/Wakeup
109 L : aliased RTS_Lock;
110 -- Protection for all components is lock L
113 end System.Task_Primitives;