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) 1991-2005 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, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, 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
38 -- tasking operations. It causes infinite loops and other problems.
40 with System.OS_Interface;
41 -- used for pthread_mutex_t
45 package System.Task_Primitives is
47 type Lock is limited private;
48 -- Should be used for implementation of protected objects
50 type RTS_Lock is limited private;
51 -- Should be used inside the runtime system. The difference between Lock
52 -- and the RTS_Lock is that the later one serves only as a semaphore so
53 -- that do not check for ceiling violations.
55 type Suspension_Object is limited private;
56 -- Should be used for the implementation of Ada.Synchronous_Task_Control
58 type Task_Body_Access is access procedure;
59 -- Pointer to the task body's entry point (or possibly a wrapper
60 -- declared local to the GNARL).
62 type Private_Data is limited private;
63 -- Any information that the GNULLI needs maintained on a per-task basis.
64 -- A component of this type is guaranteed to be included in the
65 -- Ada_Task_Control_Block.
70 Mutex : aliased System.OS_Interface.CRITICAL_SECTION;
72 Owner_Priority : Integer;
75 type Condition_Variable is new System.OS_Interface.HANDLE;
77 type RTS_Lock is new System.OS_Interface.CRITICAL_SECTION;
79 type Suspension_Object is record
81 pragma Atomic (State);
82 -- Boolean that indicates whether the object is open. This field is
83 -- marked Atomic to ensure that we can read its value without locking
84 -- the access to the Suspension_Object.
87 -- Flag showing if there is a task already suspended on this object
89 L : aliased System.OS_Interface.CRITICAL_SECTION;
90 -- Protection for ensuring mutual exclusion on the Suspension_Object
92 CV : aliased System.OS_Interface.HANDLE;
93 -- Condition variable used to queue threads until condition is signaled
96 type Private_Data is record
97 Thread : aliased System.OS_Interface.HANDLE;
98 pragma Atomic (Thread);
99 -- Thread field may be updated by two different threads of control.
100 -- (See, Enter_Task and Create_Task in s-taprop.adb).
101 -- They put the same value (thr_self value). We do not want to
102 -- use lock on those operations and the only thing we have to
103 -- make sure is that they are updated in atomic fashion.
105 Thread_Id : aliased System.OS_Interface.DWORD;
106 -- Used to provide a better tasking support in gdb
108 CV : aliased Condition_Variable;
109 -- Condition Variable used to implement Sleep/Wakeup
111 L : aliased RTS_Lock;
112 -- Protection for all components is lock L
115 end System.Task_Primitives;