1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . T A S K _ I N F O --
8 -- (Compiler Interface) --
12 -- Copyright (C) 1998-2000 Free Software Foundation, Inc. --
14 -- GNAT is free software; you can redistribute it and/or modify it under --
15 -- terms of the GNU General Public License as published by the Free Soft- --
16 -- ware Foundation; either version 2, or (at your option) any later ver- --
17 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
18 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
19 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
20 -- for more details. You should have received a copy of the GNU General --
21 -- Public License distributed with GNAT; see file COPYING. If not, write --
22 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
23 -- MA 02111-1307, USA. --
25 -- As a special exception, if other files instantiate generics from this --
26 -- unit, or you link this unit with other files to produce an executable, --
27 -- this unit does not by itself cause the resulting executable to be --
28 -- covered by the GNU General Public License. This exception does not --
29 -- however invalidate any other reasons why the executable file might be --
30 -- covered by the GNU Public License. --
32 -- GNAT was originally developed by the GNAT team at New York University. --
33 -- Extensive contributions were provided by Ada Core Technologies Inc. --
35 ------------------------------------------------------------------------------
37 -- This is a DEC Unix 4.0d version of this package.
39 -- This package contains the definitions and routines associated with the
40 -- implementation of the Task_Info pragma.
42 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
43 -- Any changes to this interface may require corresponding compiler changes.
45 with Unchecked_Deallocation
;
46 package System
.Task_Info
is
47 pragma Elaborate_Body
;
48 -- To ensure that a body is allowed
50 -----------------------------------------
51 -- Implementation of Task_Info Feature --
52 -----------------------------------------
54 -- The Task_Info pragma:
56 -- pragma Task_Info (EXPRESSION);
58 -- allows the specification on a task by task basis of a value of type
59 -- System.Task_Info.Task_Info_Type to be passed to a task when it is
60 -- created. The specification of this type, and the effect on the task
61 -- that is created is target dependent.
63 -- The Task_Info pragma appears within a task definition (compare the
64 -- definition and implementation of pragma Priority). If no such pragma
65 -- appears, then the value Task_Info_Unspecified is passed. If a pragma
66 -- is present, then it supplies an alternative value. If the argument of
67 -- the pragma is a discriminant reference, then the value can be set on
68 -- a task by task basis by supplying the appropriate discriminant value.
70 -- Note that this means that the type used for Task_Info_Type must be
71 -- suitable for use as a discriminant (i.e. a scalar or access type).
79 -- Contend only with threads in same process
82 -- Contend with all threads on same CPU
86 type Thread_Attributes
is record
87 Bind_To_Cpu_Number
: Integer;
90 -- 1-N: Bind all unbound threads to this CPU
92 Contention_Scope
: Scope_Type
;
95 type Task_Info_Type
is access all Thread_Attributes
;
96 -- Type used for passing information to task create call, using the
97 -- Task_Info pragma. This type may be specialized for individual
98 -- implementations, but it must be a type that can be used as a
99 -- discriminant (i.e. a scalar or access type).
101 type Task_Image_Type
is access String;
102 -- Used to generate a meaningful identifier for tasks that are variables
103 -- and components of variables.
105 procedure Free_Task_Image
is new
106 Unchecked_Deallocation
(String, Task_Image_Type
);
108 Unspecified_Thread_Attribute
: aliased Thread_Attributes
:=
109 Thread_Attributes
'(-1, Default_Scope);
111 Unspecified_Task_Info : constant Task_Info_Type :=
112 Unspecified_Thread_Attribute'Access;
113 -- Value passed to task in the absence of a Task_Info pragma
114 -- Don't call new here because the tasking run time has not been
115 -- elaborated yet, so calling Task_Lock is unsafe.
117 end System.Task_Info;