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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) 1991-2017, Florida State University -- | |
4b490c1e | 10 | -- Copyright (C) 1995-2020, AdaCore -- |
16707e90 AC |
11 | -- -- |
12 | -- GNAT 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 3, or (at your option) any later ver- -- | |
15 | -- sion. GNAT 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. -- | |
18 | -- -- | |
19 | -- As a special exception under Section 7 of GPL version 3, you are granted -- | |
20 | -- additional permissions described in the GCC Runtime Library Exception, -- | |
21 | -- version 3.1, as published by the Free Software Foundation. -- | |
22 | -- -- | |
23 | -- You should have received a copy of the GNU General Public License and -- | |
24 | -- a copy of the GCC Runtime Library Exception along with this program; -- | |
25 | -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- | |
26 | -- <http://www.gnu.org/licenses/>. -- | |
27 | -- -- | |
28 | -- GNARL was developed by the GNARL team at Florida State University. -- | |
29 | -- Extensive contributions were provided by Ada Core Technologies, Inc. -- | |
30 | -- -- | |
31 | ------------------------------------------------------------------------------ | |
32 | ||
33 | -- This is LynxOS Family version of this package. | |
34 | ||
35 | pragma Polling (Off); | |
36 | -- Turn off polling, we do not want ATC polling to take place during tasking | |
37 | -- operations. It causes infinite loops and other problems. | |
38 | ||
39 | with System.OS_Interface; | |
40 | ||
41 | package System.Task_Primitives is | |
42 | pragma Preelaborate; | |
43 | ||
44 | type Lock is limited private; | |
45 | -- Should be used for implementation of protected objects | |
46 | ||
47 | type RTS_Lock is limited private; | |
48 | -- Should be used inside the runtime system. The difference between Lock | |
49 | -- and the RTS_Lock is that the latter serves only as a semaphore so that | |
50 | -- we do not check for ceiling violations. | |
51 | ||
52 | type Suspension_Object is limited private; | |
53 | -- Should be used for the implementation of Ada.Synchronous_Task_Control | |
54 | ||
55 | type Task_Body_Access is access procedure; | |
56 | -- Pointer to the task body's entry point (or possibly a wrapper declared | |
57 | -- local to the GNARL). | |
58 | ||
59 | type Private_Data is limited private; | |
60 | -- Any information that the GNULLI needs maintained on a per-task basis. | |
61 | -- A component of this type is guaranteed to be included in the | |
62 | -- Ada_Task_Control_Block. | |
63 | ||
64 | subtype Task_Address is System.Address; | |
65 | Task_Address_Size : constant := Standard'Address_Size; | |
66 | -- Type used for task addresses and its size | |
67 | ||
68 | Alternate_Stack_Size : constant := System.OS_Interface.Alternate_Stack_Size; | |
69 | -- Import value from System.OS_Interface | |
70 | ||
71 | private | |
72 | ||
73 | type Lock is record | |
74 | RW : aliased System.OS_Interface.pthread_rwlock_t; | |
75 | WO : aliased System.OS_Interface.pthread_mutex_t; | |
76 | end record; | |
77 | ||
78 | type RTS_Lock is new System.OS_Interface.pthread_mutex_t; | |
79 | ||
80 | type Suspension_Object is record | |
81 | State : Boolean; | |
82 | pragma Atomic (State); | |
83 | -- Boolean that indicates whether the object is open. This field is | |
84 | -- marked Atomic to ensure that we can read its value without locking | |
85 | -- the access to the Suspension_Object. | |
86 | ||
87 | Waiting : Boolean; | |
88 | -- Flag showing if there is a task already suspended on this object | |
89 | ||
90 | L : aliased System.OS_Interface.pthread_mutex_t; | |
91 | -- Protection for ensuring mutual exclusion on the Suspension_Object | |
92 | ||
93 | CV : aliased System.OS_Interface.pthread_cond_t; | |
94 | -- Condition variable used to queue threads until condition is signaled | |
95 | end record; | |
96 | ||
97 | type Private_Data is limited record | |
98 | Thread : aliased System.OS_Interface.pthread_t; | |
99 | pragma Atomic (Thread); | |
100 | -- Thread field may be updated by two different threads of control. | |
101 | -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same | |
102 | -- value (thr_self value). We do not want to use lock on those | |
103 | -- operations and the only thing we have to make sure is that they are | |
104 | -- updated in atomic fashion. | |
105 | ||
106 | LWP : aliased System.OS_Interface.pthread_t; | |
107 | -- The purpose of this field is to provide a better tasking support on | |
108 | -- gdb. The order of the two first fields (Thread and LWP) is important. | |
109 | -- On targets where lwp is not relevant, this is equivalent to Thread. | |
110 | ||
111 | CV : aliased System.OS_Interface.pthread_cond_t; | |
112 | -- Should be commented ??? (in all versions of taspri) | |
113 | ||
114 | L : aliased RTS_Lock; | |
115 | -- Protection for all components is lock L | |
116 | end record; | |
117 | ||
118 | end System.Task_Primitives; |