File : s-taspri-posix-noaltstack.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) 1991-1994, Florida State University --
10 -- Copyright (C) 1995-2014, AdaCore --
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 -- --
20 -- --
21 -- --
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 a POSIX-like version of this package where no alternate stack
34 -- is needed for stack checking.
35
36 -- Note: this file can only be used for POSIX compliant systems
37
38 pragma Polling (Off);
39 -- Turn off polling, we do not want ATC polling to take place during tasking
40 -- operations. It causes infinite loops and other problems.
41
42 with System.OS_Interface;
43
44 package System.Task_Primitives is
45 pragma Preelaborate;
46
47 type Lock is limited private;
48 -- Should be used for implementation of protected objects
49
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.
54
55 type Suspension_Object is limited private;
56 -- Should be used for the implementation of Ada.Synchronous_Task_Control
57
58 type Task_Body_Access is access procedure;
59 -- Pointer to the task body's entry point (or possibly a wrapper declared
60 -- local to the GNARL).
61
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.
66
67 subtype Task_Address is System.Address;
68 Task_Address_Size : constant := Standard'Address_Size;
69 -- Type used for task addresses and its size
70
71 Alternate_Stack_Size : constant := 0;
72 -- No alternate signal stack is used on this platform
73
74 private
75
76 type Lock is record
77 WO : aliased System.OS_Interface.pthread_mutex_t;
78 RW : aliased System.OS_Interface.pthread_rwlock_t;
79 end record;
80
81 type RTS_Lock is new System.OS_Interface.pthread_mutex_t;
82
83 type Suspension_Object is record
84 State : Boolean;
85 pragma Atomic (State);
86 -- Boolean that indicates whether the object is open. This field is
87 -- marked Atomic to ensure that we can read its value without locking
88 -- the access to the Suspension_Object.
89
90 Waiting : Boolean;
91 -- Flag showing if there is a task already suspended on this object
92
93 L : aliased System.OS_Interface.pthread_mutex_t;
94 -- Protection for ensuring mutual exclusion on the Suspension_Object
95
96 CV : aliased System.OS_Interface.pthread_cond_t;
97 -- Condition variable used to queue threads until condition is signaled
98 end record;
99
100 type Private_Data is limited record
101 Thread : aliased System.OS_Interface.pthread_t;
102 pragma Atomic (Thread);
103 -- Thread field may be updated by two different threads of control.
104 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
105 -- value (thr_self value). We do not want to use lock on those
106 -- operations and the only thing we have to make sure is that they are
107 -- updated in atomic fashion.
108
109 LWP : aliased System.Address;
110 -- The purpose of this field is to provide a better tasking support on
111 -- gdb. The order of the two first fields (Thread and LWP) is important.
112 -- On targets where lwp is not relevant, this is equivalent to Thread.
113
114 CV : aliased System.OS_Interface.pthread_cond_t;
115 -- Should be commented ??? (in all versions of taspri)
116
117 L : aliased RTS_Lock;
118 -- Protection for all components is lock L
119 end record;
120
121 end System.Task_Primitives;