gcc/ada/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, 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 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.                                              --
  21 --                                                                          --
  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.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  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.
  37
  38 --  Note: the compiler generates direct calls to this interface, via Rtsfind.
  39 --  Any changes to this interface may require corresponding compiler changes.
  40
  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.
  43
  44 --  This is the GNU/Linux version of this module.
  45
  46 with System.OS_Interface;
  47
  48 package System.Task_Info is
  49    pragma Preelaborate;
  50    pragma Elaborate_Body;
  51    --  To ensure that a body is allowed
  52
  53    --  Windows provides a way to define the ideal processor to use for a given
  54    --  thread. The ideal processor is not necessarily the one that will be used
  55    --  by the OS but the OS will always try to schedule this thread to the
  56    --  specified processor if it is available.
  57
  58    --  The Task_Info pragma:
  59
  60    --    pragma Task_Info (EXPRESSION);
  61
  62    --  allows the specification on a task by task basis of a value of type
  63    --  System.Task_Info.Task_Info_Type to be passed to a task when it is
  64    --  created. The specification of this type, and the effect on the task
  65    --  that is created is target dependent.
  66
  67    --  The Task_Info pragma appears within a task definition (compare the
  68    --  definition and implementation of pragma Priority). If no such pragma
  69    --  appears, then the value Unspecified_Task_Info is passed. If a pragma
  70    --  is present, then it supplies an alternative value. If the argument of
  71    --  the pragma is a discriminant reference, then the value can be set on
  72    --  a task by task basis by supplying the appropriate discriminant value.
  73
  74    --  Note that this means that the type used for Task_Info_Type must be
  75    --  suitable for use as a discriminant (i.e. a scalar or access type).
  76
  77    -----------------------
  78    -- Thread Attributes --
  79    -----------------------
  80
  81    subtype CPU_Set is System.OS_Interface.cpu_set_t;
  82
  83    Any_CPU : constant CPU_Set := (bits => (others => True));
  84    No_CPU  : constant CPU_Set := (bits => (others => False));
  85
  86    Invalid_CPU_Number : exception;
  87    --  Raised when an invalid CPU mask has been specified
  88    --  i.e. An empty CPU set
  89
  90    type Thread_Attributes is record
  91       CPU_Affinity : aliased CPU_Set := Any_CPU;
  92    end record;
  93
  94    Default_Thread_Attributes : constant Thread_Attributes := (others => <>);
  95
  96    type Task_Info_Type is access all Thread_Attributes;
  97
  98    Unspecified_Task_Info : constant Task_Info_Type := null;
  99
 100    function Number_Of_Processors return Positive;
 101    --  Returns the number of processors on the running host
 102
 103 end System.Task_Info;