1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . T A S K _ I N F O --
9 -- Copyright (C) 1992-2005 Free Software Foundation, Inc. --
11 -- GNAT 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. GNAT 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 GNAT; 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 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 -- This package contains the definitions and routines associated with the
35 -- implementation and use of the Task_Info pragma. It is specialized
36 -- appropriately for targets that make use of this pragma.
38 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
39 -- Any changes to this interface may require corresponding compiler changes.
41 -- This unit may be used directly from an application program by providing
42 -- an appropriate WITH, and the interface can be expected to remain stable.
44 package System
.Task_Info
is
46 pragma Elaborate_Body
;
47 -- To ensure that a body is allowed
49 -----------------------------------------
50 -- Implementation of Task_Info Feature --
51 -----------------------------------------
53 -- The Task_Info pragma:
55 -- pragma Task_Info (EXPRESSION);
57 -- allows the specification on a task by task basis of a value of type
58 -- System.Task_Info.Task_Info_Type to be passed to a task when it is
59 -- created. The specification of this type, and the effect on the task
60 -- that is created is target dependent.
62 -- The Task_Info pragma appears within a task definition (compare the
63 -- definition and implementation of pragma Priority). If no such pragma
64 -- appears, then the value Task_Info_Unspecified is passed. If a pragma
65 -- is present, then it supplies an alternative value. If the argument of
66 -- the pragma is a discriminant reference, then the value can be set on
67 -- a task by task basis by supplying the appropriate discriminant value.
69 -- Note that this means that the type used for Task_Info_Type must be
70 -- suitable for use as a discriminant (i.e. a scalar or access type).
78 -- Contend only with threads in same process
81 -- Contend with all threads on same CPU
85 type Task_Info_Type
is new Scope_Type
;
86 -- Type used for passing information to task create call, using the
87 -- Task_Info pragma. This type may be specialized for individual
88 -- implementations, but it must be a type that can be used as a
89 -- discriminant (i.e. a scalar or access type).
91 Unspecified_Task_Info
: constant Task_Info_Type
:= Default_Scope
;
92 -- Value passed to task in the absence of a Task_Info pragma