1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . T A S K _ I N F O --
8 -- (Compiler Interface) --
10 -- Copyright (C) 1998-2005 Free Software Foundation, Inc. --
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 2, 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. 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 GNAT; 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 -- GNAT was originally developed by the GNAT team at New York University. --
31 -- Extensive contributions were provided by Ada Core Technologies Inc. --
33 ------------------------------------------------------------------------------
35 -- This package contains the definitions and routines associated with the
36 -- implementation and use of the Task_Info pragma. It is specialized
37 -- appropriately for targets that make use of this pragma.
39 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
40 -- Any changes to this interface may require corresponding compiler changes.
42 -- This unit may be used directly from an application program by providing
43 -- an appropriate WITH, and the interface can be expected to remain stable.
45 -- This is a DEC Unix 4.0d version of this package.
47 package System
.Task_Info
is
49 pragma Elaborate_Body
;
50 -- To ensure that a body is allowed
52 -----------------------------------------
53 -- Implementation of Task_Info Feature --
54 -----------------------------------------
56 -- The Task_Info pragma:
58 -- pragma Task_Info (EXPRESSION);
60 -- allows the specification on a task by task basis of a value of type
61 -- System.Task_Info.Task_Info_Type to be passed to a task when it is
62 -- created. The specification of this type, and the effect on the task
63 -- that is created is target dependent.
65 -- The Task_Info pragma appears within a task definition (compare the
66 -- definition and implementation of pragma Priority). If no such pragma
67 -- appears, then the value Task_Info_Unspecified is passed. If a pragma
68 -- is present, then it supplies an alternative value. If the argument of
69 -- the pragma is a discriminant reference, then the value can be set on
70 -- a task by task basis by supplying the appropriate discriminant value.
72 -- Note that this means that the type used for Task_Info_Type must be
73 -- suitable for use as a discriminant (i.e. a scalar or access type).
81 -- Contend only with threads in same process
84 -- Contend with all threads on same CPU
88 type Thread_Attributes
is record
89 Bind_To_Cpu_Number
: Integer;
92 -- 1-N: Bind all unbound threads to this CPU
94 Contention_Scope
: Scope_Type
;
97 type Task_Info_Type
is access all Thread_Attributes
;
98 -- Type used for passing information to task create call, using the
99 -- Task_Info pragma. This type may be specialized for individual
100 -- implementations, but it must be a type that can be used as a
101 -- discriminant (i.e. a scalar or access type).
103 Unspecified_Thread_Attribute
: aliased Thread_Attributes
:=
104 Thread_Attributes
'(-1, Default_Scope);
106 Unspecified_Task_Info : constant Task_Info_Type :=
107 Unspecified_Thread_Attribute'Access;
108 -- Value passed to task in the absence of a Task_Info pragma
109 -- Don't call new here because the tasking run time has not been
110 -- elaborated yet, so calling Task_Lock is unsafe.
112 end System.Task_Info;