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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                     S Y S T E M . T A S K _ I N F O                      --

--                                                                          --

--                                 S p e c                                  --

--                           (Compiler Interface)                           --

--                                                                          --

--         Copyright (C) 1998-2009, Free Software Foundation, Inc.          --

--                                                                          --

-- GNAT is free software;  you can  redistribute it  and/or modify it under --

-- terms of the  GNU General Public License as published  by the Free Soft- --

-- ware  Foundation;  either version 3,  or (at your option) any later ver- --

-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --

-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --

-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  This package contains the definitions and routines associated with the

--  implementation and use of the Task_Info pragma. It is specialized

--  appropriately for targets that make use of this pragma.

--  Note: the compiler generates direct calls to this interface, via Rtsfind.

--  Any changes to this interface may require corresponding compiler changes.

--  This unit may be used directly from an application program by providing

--  an appropriate WITH, and the interface can be expected to remain stable.

--  This is a DEC Unix 4.0d version of this package

package System.Task_Info is

   pragma Preelaborate;

   pragma Elaborate_Body;

   --  To ensure that a body is allowed

   -----------------------------------------

   -- Implementation of Task_Info Feature --

   -----------------------------------------

   --  The Task_Info pragma:

   --    pragma Task_Info (EXPRESSION);

   --  allows the specification on a task by task basis of a value of type

   --  System.Task_Info.Task_Info_Type to be passed to a task when it is

   --  created. The specification of this type, and the effect on the task

   --  that is created is target dependent.

   --  The Task_Info pragma appears within a task definition (compare the

   --  definition and implementation of pragma Priority). If no such pragma

   --  appears, then the value Unspecified_Task_Info is passed. If a pragma

   --  is present, then it supplies an alternative value. If the argument of

   --  the pragma is a discriminant reference, then the value can be set on

   --  a task by task basis by supplying the appropriate discriminant value.

   --  Note that this means that the type used for Task_Info_Type must be

   --  suitable for use as a discriminant (i.e. a scalar or access type).

   ------------------

   -- Declarations --

   ------------------

   type Scope_Type is

     (Process_Scope,

      --  Contend only with threads in same process

      System_Scope,

      --  Contend with all threads on same CPU

      Default_Scope);

   type Thread_Attributes is record

      Bind_To_Cpu_Number : Integer;

      --   -1: Do nothing

      --    0: Unbind

      --  1-N: Bind all unbound threads to this CPU

      Contention_Scope   : Scope_Type;

   end record;

   type Task_Info_Type is access all Thread_Attributes;

   --  Type used for passing information to task create call, using the

   --  Task_Info pragma. This type may be specialized for individual

   --  implementations, but it must be a type that can be used as a

   --  discriminant (i.e. a scalar or access type).

   Unspecified_Thread_Attribute : aliased Thread_Attributes :=

     Thread_Attributes'(-1, Default_Scope);

   Unspecified_Task_Info : constant Task_Info_Type :=

     Unspecified_Thread_Attribute'Access;

   --  Value passed to task in the absence of a Task_Info pragma

   --  Don't call new here because the tasking run time has not been

   --  elaborated yet, so calling Task_Lock is unsafe.

end System.Task_Info;