File : s-taspri-vxworks.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT 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) 2001-2014, 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 3, or (at your option) any later ver- --
14 -- sion. GNAT 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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
26 -- --
27 -- GNARL was developed by the GNARL team at Florida State University. --
28 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This is a VxWorks version of this package
33
34 pragma Polling (Off);
35 -- Turn off polling, we do not want ATC polling to take place during tasking
36 -- operations. It causes infinite loops and other problems.
37
38 with System.OS_Interface;
39
40 package System.Task_Primitives is
41 pragma Preelaborate;
42
43 type Lock is limited private;
44 -- Should be used for implementation of protected objects
45
46 type RTS_Lock is limited private;
47 -- Should be used inside the runtime system. The difference between Lock
48 -- and the RTS_Lock is that the later one serves only as a semaphore so
49 -- that do not check for ceiling violations.
50
51 type Suspension_Object is limited private;
52 -- Should be used for the implementation of Ada.Synchronous_Task_Control
53
54 type Task_Body_Access is access procedure;
55 -- Pointer to the task body's entry point (or possibly a wrapper
56 -- declared local to the GNARL).
57
58 type Private_Data is limited private;
59 -- Any information that the GNULLI needs maintained on a per-task basis.
60 -- A component of this type is guaranteed to be included in the
61 -- Ada_Task_Control_Block.
62
63 subtype Task_Address is System.Address;
64 Task_Address_Size : constant := Standard'Address_Size;
65 -- Type used for task addresses and its size
66
67 Alternate_Stack_Size : constant := 0;
68 -- No alternate signal stack is used on this platform
69
70 private
71
72 type Priority_Type is (Prio_None, Prio_Protect, Prio_Inherit);
73
74 type Lock is record
75 Mutex : System.OS_Interface.SEM_ID;
76 Protocol : Priority_Type;
77
78 Prio_Ceiling : System.OS_Interface.int;
79 -- Priority ceiling of lock
80 end record;
81
82 type RTS_Lock is new Lock;
83
84 type Suspension_Object is record
85 State : Boolean;
86 pragma Atomic (State);
87 -- Boolean that indicates whether the object is open. This field is
88 -- marked Atomic to ensure that we can read its value without locking
89 -- the access to the Suspension_Object.
90
91 Waiting : Boolean;
92 -- Flag showing if there is a task already suspended on this object
93
94 L : aliased System.OS_Interface.SEM_ID;
95 -- Protection for ensuring mutual exclusion on the Suspension_Object
96
97 CV : aliased System.OS_Interface.SEM_ID;
98 -- Condition variable used to queue threads until condition is signaled
99 end record;
100
101 type Private_Data is limited record
102 Thread : aliased System.OS_Interface.t_id := 0;
103 pragma Atomic (Thread);
104 -- Thread field may be updated by two different threads of control.
105 -- (See, Enter_Task and Create_Task in s-taprop.adb).
106 -- They put the same value (thr_self value). We do not want to
107 -- use lock on those operations and the only thing we have to
108 -- make sure is that they are updated in atomic fashion.
109
110 LWP : aliased System.OS_Interface.t_id := 0;
111 -- The purpose of this field is to provide a better tasking support on
112 -- gdb. The order of the two first fields (Thread and LWP) is important.
113 -- On targets where lwp is not relevant, this is equivalent to Thread.
114
115 CV : aliased System.OS_Interface.SEM_ID;
116
117 L : aliased RTS_Lock;
118 -- Protection for all components is lock L
119 end record;
120
121 end System.Task_Primitives;