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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) 1998-2000 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 2, 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. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
-- This is a DEC Unix 4.0d version of this package.
-- This package contains the definitions and routines associated with the
-- implementation of the Task_Info pragma.
-- Note: the compiler generates direct calls to this interface, via Rtsfind.
-- Any changes to this interface may require corresponding compiler changes.
with Unchecked_Deallocation;
package System.Task_Info is
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 Task_Info_Unspecified 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).
type Task_Image_Type is access String;
-- Used to generate a meaningful identifier for tasks that are variables
-- and components of variables.
procedure Free_Task_Image is new
Unchecked_Deallocation (String, Task_Image_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;
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