File : s-tasinf-linux.ads
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- S Y S T E M . T A S K _ I N F O --
6 -- --
7 -- S p e c --
8 -- --
9 -- Copyright (C) 2007-2014, Free Software Foundation, Inc. --
10 -- --
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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
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/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
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.
35
36 -- Note: the compiler generates direct calls to this interface, via Rtsfind.
37 -- Any changes to this interface may require corresponding compiler changes.
38
39 -- The functionality in this unit is now provided by the predefined package
40 -- System.Multiprocessors and the CPU aspect. This package is obsolescent.
41
42 -- This is the GNU/Linux version of this module
43
44 with System.OS_Interface;
45
46 package System.Task_Info is
47 pragma Obsolescent (Task_Info, "use System.Multiprocessors and CPU aspect");
48 pragma Preelaborate;
49 pragma Elaborate_Body;
50 -- To ensure that a body is allowed
51
52 -- The Linux kernel provides a way to define the ideal processor to use for
53 -- a given thread. The ideal processor is not necessarily the one that will
54 -- be used by the OS but the OS will always try to schedule this thread to
55 -- the specified processor if it is available.
56
57 -- The Task_Info pragma:
58
59 -- pragma Task_Info (EXPRESSION);
60
61 -- allows the specification on a task by task basis of a value of type
62 -- System.Task_Info.Task_Info_Type to be passed to a task when it is
63 -- created. The specification of this type, and the effect on the task
64 -- that is created is target dependent.
65
66 -- The Task_Info pragma appears within a task definition (compare the
67 -- definition and implementation of pragma Priority). If no such pragma
68 -- appears, then the value Unspecified_Task_Info is passed. If a pragma
69 -- is present, then it supplies an alternative value. If the argument of
70 -- the pragma is a discriminant reference, then the value can be set on
71 -- a task by task basis by supplying the appropriate discriminant value.
72
73 -- Note that this means that the type used for Task_Info_Type must be
74 -- suitable for use as a discriminant (i.e. a scalar or access type).
75
76 -----------------------
77 -- Thread Attributes --
78 -----------------------
79
80 subtype CPU_Set is System.OS_Interface.cpu_set_t;
81
82 Any_CPU : constant CPU_Set := (bits => (others => True));
83 No_CPU : constant CPU_Set := (bits => (others => False));
84
85 Invalid_CPU_Number : exception;
86 -- Raised when an invalid CPU mask has been specified
87 -- i.e. An empty CPU set
88
89 type Thread_Attributes is record
90 CPU_Affinity : aliased CPU_Set := Any_CPU;
91 end record;
92
93 Default_Thread_Attributes : constant Thread_Attributes := (others => <>);
94
95 type Task_Info_Type is access all Thread_Attributes;
96
97 Unspecified_Task_Info : constant Task_Info_Type := null;
98
99 function Number_Of_Processors return Positive;
100 -- Returns the number of processors on the running host
101
102 end System.Task_Info;