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) 1992-2008, 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 tasking
40 -- operations. It causes infinite loops and other problems.
42 with Ada.Unchecked_Conversion;
44 with System.OS_Interface;
46 package System.Task_Primitives is
49 type Lock is limited private;
50 type Lock_Ptr is access all Lock;
51 -- Should be used for implementation of protected objects
53 type RTS_Lock is limited private;
54 type RTS_Lock_Ptr is access all RTS_Lock;
55 -- Should be used inside the runtime system. The difference between Lock
56 -- and the RTS_Lock is that the later one serves only as a semaphore so
57 -- that do not check for ceiling violations.
59 function To_Lock_Ptr is
60 new Ada.Unchecked_Conversion (RTS_Lock_Ptr, Lock_Ptr);
62 type Suspension_Object is limited private;
63 -- Should be used for the implementation of Ada.Synchronous_Task_Control
65 type Task_Body_Access is access procedure;
66 -- Pointer to the task body's entry point (or possibly a wrapper
67 -- declared local to the GNARL).
69 type Private_Data is limited private;
70 -- Any information that the GNULLI needs maintained on a per-task basis.
71 -- A component of this type is guaranteed to be included in the
72 -- Ada_Task_Control_Block.
74 subtype Task_Address is System.Address;
75 -- In some versions of Task_Primitives, notably for VMS, Task_Address is
76 -- the short version of address defined in System.Aux_DEC. To avoid
77 -- dragging Aux_DEC into tasking packages a tasking specific subtype is
80 Task_Address_Size : constant := Standard'Address_Size;
81 -- The size of Task_Address
83 Alternate_Stack_Size : constant := 0;
84 -- No alternate signal stack is used on this platform
88 type Private_Task_Serial_Number is mod 2 ** 64;
89 -- Used to give each task a unique serial number
91 type Base_Lock is new System.OS_Interface.mutex_t;
93 type Owner_Int is new Integer;
94 for Owner_Int'Alignment use Standard'Maximum_Alignment;
96 type Owner_ID is access all Owner_Int;
98 function To_Owner_ID is
99 new Ada.Unchecked_Conversion (System.Address, Owner_ID);
102 L : aliased Base_Lock;
103 Ceiling : System.Any_Priority := System.Any_Priority'First;
104 Saved_Priority : System.Any_Priority := System.Any_Priority'First;
107 Level : Private_Task_Serial_Number := 0;
109 Frozen : Boolean := False;
112 type RTS_Lock is new Lock;
114 type Suspension_Object is record
116 pragma Atomic (State);
117 -- Boolean that indicates whether the object is open. This field is
118 -- marked Atomic to ensure that we can read its value without locking
119 -- the access to the Suspension_Object.
122 -- Flag showing if there is a task already suspended on this object
124 L : aliased System.OS_Interface.mutex_t;
125 -- Protection for ensuring mutual exclusion on the Suspension_Object
127 CV : aliased System.OS_Interface.cond_t;
128 -- Condition variable used to queue threads until condition is signaled
131 -- Note that task support on gdb relies on the fact that the first two
132 -- fields of Private_Data are Thread and LWP.
134 type Private_Data is record
135 Thread : aliased System.OS_Interface.thread_t;
136 pragma Atomic (Thread);
137 -- Thread field may be updated by two different threads of control.
138 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
139 -- value (thr_self value). We do not want to use lock on those
140 -- operations and the only thing we have to make sure is that they are
141 -- updated in atomic fashion.
143 LWP : System.OS_Interface.lwpid_t;
144 -- The LWP id of the thread. Set by self in Enter_Task
146 CV : aliased System.OS_Interface.cond_t;
147 L : aliased RTS_Lock;
148 -- Protection for all components is lock L
150 Active_Priority : System.Any_Priority := System.Any_Priority'First;
151 -- Simulated active priority, used iff Priority_Ceiling_Support is True
155 Wakeups : Natural := 0;
158 end System.Task_Primitives;