1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . T A S K _ I N F O --
9 -- Copyright (C) 2007-2012, 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 3, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- This package contains the definitions and routines associated with the
33 -- implementation and use of the Task_Info pragma. It is specialized
34 -- appropriately for targets that make use of this pragma.
36 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
37 -- Any changes to this interface may require corresponding compiler changes.
39 -- This unit may be used directly from an application program by providing
40 -- an appropriate WITH, and the interface can be expected to remain stable.
42 -- This is the GNU/Linux version of this module
44 with System
.OS_Interface
;
46 package System
.Task_Info
is
48 pragma Elaborate_Body
;
49 -- To ensure that a body is allowed
51 -- The Linux kernel provides a way to define the ideal processor to use for
52 -- a given thread. The ideal processor is not necessarily the one that will
53 -- be used by the OS but the OS will always try to schedule this thread to
54 -- the specified processor if it is available.
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 Unspecified_Task_Info 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).
75 -----------------------
76 -- Thread Attributes --
77 -----------------------
79 subtype CPU_Set
is System
.OS_Interface
.cpu_set_t
;
81 Any_CPU
: constant CPU_Set
:= (bits
=> (others => True));
82 No_CPU
: constant CPU_Set
:= (bits
=> (others => False));
84 Invalid_CPU_Number
: exception;
85 -- Raised when an invalid CPU mask has been specified
86 -- i.e. An empty CPU set
88 type Thread_Attributes
is record
89 CPU_Affinity
: aliased CPU_Set
:= Any_CPU
;
92 Default_Thread_Attributes
: constant Thread_Attributes
:= (others => <>);
94 type Task_Info_Type
is access all Thread_Attributes
;
96 Unspecified_Task_Info
: constant Task_Info_Type
:= null;
98 function Number_Of_Processors
return Positive;
99 -- Returns the number of processors on the running host
101 end System
.Task_Info
;