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) 1995-2011, AdaCore --
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. --
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. --
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/>. --
28 -- GNARL was developed by the GNARL team at Florida State University. --
29 -- Extensive contributions were provided by Ada Core Technologies, Inc. --
31 ------------------------------------------------------------------------------
33 -- This is a POSIX-like version of this package
35 -- Note: this file can only be used for POSIX compliant systems
38 -- Turn off polling, we do not want ATC polling to take place during tasking
39 -- operations. It causes infinite loops and other problems.
41 with System
.OS_Interface
;
43 package System
.Task_Primitives
is
46 type Lock
is limited private;
47 -- Should be used for implementation of protected objects
49 type RTS_Lock
is limited private;
50 -- Should be used inside the runtime system. The difference between Lock
51 -- and the RTS_Lock is that the later one serves only as a semaphore so
52 -- that do not check for ceiling violations.
54 type Suspension_Object
is limited private;
55 -- Should be used for the implementation of Ada.Synchronous_Task_Control
57 type Task_Body_Access
is access procedure;
58 -- Pointer to the task body's entry point (or possibly a wrapper declared
59 -- local to the GNARL).
61 type Private_Data
is limited private;
62 -- Any information that the GNULLI needs maintained on a per-task basis.
63 -- A component of this type is guaranteed to be included in the
64 -- Ada_Task_Control_Block.
66 subtype Task_Address
is System
.Address
;
67 -- In some versions of Task_Primitives, notably for VMS, Task_Address is
68 -- the short version of address defined in System.Aux_DEC. To avoid
69 -- dragging Aux_DEC into tasking packages a tasking specific subtype is
72 Task_Address_Size
: constant := Standard
'Address_Size;
73 -- The size of Task_Address
75 Alternate_Stack_Size
: constant := System
.OS_Interface
.Alternate_Stack_Size
;
76 -- Import value from System.OS_Interface
81 RW
: aliased System
.OS_Interface
.pthread_rwlock_t
;
82 WO
: aliased System
.OS_Interface
.pthread_mutex_t
;
85 type RTS_Lock
is new System
.OS_Interface
.pthread_mutex_t
;
87 type Suspension_Object
is record
89 pragma Atomic
(State
);
90 -- Boolean that indicates whether the object is open. This field is
91 -- marked Atomic to ensure that we can read its value without locking
92 -- the access to the Suspension_Object.
95 -- Flag showing if there is a task already suspended on this object
97 L
: aliased System
.OS_Interface
.pthread_mutex_t
;
98 -- Protection for ensuring mutual exclusion on the Suspension_Object
100 CV
: aliased System
.OS_Interface
.pthread_cond_t
;
101 -- Condition variable used to queue threads until condition is signaled
104 type Private_Data
is record
105 Thread
: aliased System
.OS_Interface
.pthread_t
;
106 pragma Atomic
(Thread
);
107 -- Thread field may be updated by two different threads of control.
108 -- (See, Enter_Task and Create_Task in s-taprop.adb). They put the same
109 -- value (thr_self value). We do not want to use lock on those
110 -- operations and the only thing we have to make sure is that they are
111 -- updated in atomic fashion.
113 LWP
: aliased System
.Address
;
114 -- The purpose of this field is to provide a better tasking support on
115 -- gdb. The order of the two first fields (Thread and LWP) is important.
116 -- On targets where lwp is not relevant, this is equivalent to Thread.
118 CV
: aliased System
.OS_Interface
.pthread_cond_t
;
119 -- Should be commented ??? (in all versions of taspri)
121 L
: aliased RTS_Lock
;
122 -- Protection for all components is lock L
125 end System
.Task_Primitives
;