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) 1991-1994, Florida State University --
10 -- Copyright (C) 1995-2005, AdaCore --
12 -- GNARL 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 2, or (at your option) any later ver- --
15 -- sion. GNARL 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. See the GNU General Public License --
18 -- for more details. You should have received a copy of the GNU General --
19 -- Public License distributed with GNARL; see file COPYING. If not, write --
20 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
21 -- Boston, MA 02110-1301, USA. --
23 -- As a special exception, if other files instantiate generics from this --
24 -- unit, or you link this unit with other files to produce an executable, --
25 -- this unit does not by itself cause the resulting executable to be --
26 -- covered by the GNU General Public License. This exception does not --
27 -- however invalidate any other reasons why the executable file might be --
28 -- covered by the GNU Public License. --
30 -- GNARL was developed by the GNARL team at Florida State University. --
31 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
33 ------------------------------------------------------------------------------
35 -- This is a POSIX-like version of this package
37 -- Note: this file can only be used for POSIX compliant systems
40 -- Turn off polling, we do not want ATC polling to take place during
41 -- tasking operations. It causes infinite loops and other problems.
43 with System.OS_Interface;
44 -- used for pthread_mutex_t
48 package System.Task_Primitives is
50 type Lock is limited private;
51 -- Should be used for implementation of protected objects
53 type RTS_Lock is limited private;
54 -- Should be used inside the runtime system. The difference between Lock
55 -- and the RTS_Lock is that the later one serves only as a semaphore so
56 -- that do not check for ceiling violations.
58 type Suspension_Object is limited private;
59 -- Should be used for the implementation of Ada.Synchronous_Task_Control
61 type Task_Body_Access is access procedure;
62 -- Pointer to the task body's entry point (or possibly a wrapper declared
63 -- local to the GNARL).
65 type Private_Data is limited private;
66 -- Any information that the GNULLI needs maintained on a per-task basis.
67 -- A component of this type is guaranteed to be included in the
68 -- Ada_Task_Control_Block.
72 type Lock is new System.OS_Interface.pthread_mutex_t;
73 type RTS_Lock is new System.OS_Interface.pthread_mutex_t;
75 type Suspension_Object is record
77 pragma Atomic (State);
78 -- Boolean that indicates whether the object is open. This field is
79 -- marked Atomic to ensure that we can read its value without locking
80 -- the access to the Suspension_Object.
83 -- Flag showing if there is a task already suspended on this object
85 L : aliased System.OS_Interface.pthread_mutex_t;
86 -- Protection for ensuring mutual exclusion on the Suspension_Object
88 CV : aliased System.OS_Interface.pthread_cond_t;
89 -- Condition variable used to queue threads until condition is signaled
92 type Private_Data is record
93 Thread : aliased System.OS_Interface.pthread_t;
94 pragma Atomic (Thread);
95 -- Thread field may be updated by two different threads of control.
96 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
97 -- value (thr_self value). We do not want to use lock on those
98 -- operations and the only thing we have to make sure is that they are
99 -- updated in atomic fashion.
101 LWP : aliased System.Address;
102 -- The purpose of this field is to provide a better tasking support on
103 -- gdb. The order of the two first fields (Thread and LWP) is important.
104 -- On targets where lwp is not relevant, this is equivalent to Thread.
106 CV : aliased System.OS_Interface.pthread_cond_t;
107 -- Should be commented ??? (in all versions of taspri)
109 L : aliased RTS_Lock;
110 -- Protection for all components is lock L
113 end System.Task_Primitives;