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) 1992-2005, 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, 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 Solaris version of this package
36 -- This package provides low-level support for most tasking features
39 -- Turn off polling, we do not want ATC polling to take place during
40 -- tasking operations. It causes infinite loops and other problems.
42 with System
.OS_Interface
;
47 with Unchecked_Conversion
;
49 package System
.Task_Primitives
is
52 type Lock
is limited private;
53 type Lock_Ptr
is access all Lock
;
54 -- Should be used for implementation of protected objects
56 type RTS_Lock
is limited private;
57 type RTS_Lock_Ptr
is access all RTS_Lock
;
58 -- Should be used inside the runtime system. The difference between Lock
59 -- and the RTS_Lock is that the later one serves only as a semaphore so
60 -- that do not check for ceiling violations.
62 function To_Lock_Ptr
is new Unchecked_Conversion
(RTS_Lock_Ptr
, Lock_Ptr
);
64 type Suspension_Object
is limited private;
65 -- Should be used for the implementation of Ada.Synchronous_Task_Control
67 type Task_Body_Access
is access procedure;
68 -- Pointer to the task body's entry point (or possibly a wrapper
69 -- declared local to the GNARL).
71 type Private_Data
is limited private;
72 -- Any information that the GNULLI needs maintained on a per-task basis.
73 -- A component of this type is guaranteed to be included in the
74 -- Ada_Task_Control_Block.
78 type Private_Task_Serial_Number
is mod 2 ** 64;
79 -- Used to give each task a unique serial number
81 type Base_Lock
is new System
.OS_Interface
.mutex_t
;
83 type Owner_Int
is new Integer;
84 for Owner_Int
'Alignment use Standard
'Maximum_Alignment;
86 type Owner_ID
is access all Owner_Int
;
88 function To_Owner_ID
is
89 new Unchecked_Conversion
(System
.Address
, Owner_ID
);
92 L
: aliased Base_Lock
;
93 Ceiling
: System
.Any_Priority
:= System
.Any_Priority
'First;
94 Saved_Priority
: System
.Any_Priority
:= System
.Any_Priority
'First;
97 Level
: Private_Task_Serial_Number
:= 0;
99 Frozen
: Boolean := False;
102 type RTS_Lock
is new Lock
;
104 type Suspension_Object
is record
106 pragma Atomic
(State
);
107 -- Boolean that indicates whether the object is open. This field is
108 -- marked Atomic to ensure that we can read its value without locking
109 -- the access to the Suspension_Object.
112 -- Flag showing if there is a task already suspended on this object
114 L
: aliased System
.OS_Interface
.mutex_t
;
115 -- Protection for ensuring mutual exclusion on the Suspension_Object
117 CV
: aliased System
.OS_Interface
.cond_t
;
118 -- Condition variable used to queue threads until condition is signaled
121 -- Note that task support on gdb relies on the fact that the first two
122 -- fields of Private_Data are Thread and LWP.
124 type Private_Data
is record
125 Thread
: aliased System
.OS_Interface
.thread_t
;
126 pragma Atomic
(Thread
);
127 -- Thread field may be updated by two different threads of control.
128 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
129 -- value (thr_self value). We do not want to use lock on those
130 -- operations and the only thing we have to make sure is that they are
131 -- updated in atomic fashion.
133 LWP
: System
.OS_Interface
.lwpid_t
;
134 -- The LWP id of the thread. Set by self in Enter_Task
136 CV
: aliased System
.OS_Interface
.cond_t
;
137 L
: aliased RTS_Lock
;
138 -- Protection for all components is lock L
140 Active_Priority
: System
.Any_Priority
:= System
.Any_Priority
'First;
141 -- Simulated active priority, used iff Priority_Ceiling_Support is True
145 Wakeups
: Natural := 0;
148 end System
.Task_Primitives
;