118 lines
5.6 KiB
Ada
118 lines
5.6 KiB
Ada
------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . T A S K _ I N F O --
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-- --
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-- S p e c --
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-- (Compiler Interface) --
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-- --
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-- $Revision: 1.5 $
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-- --
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-- Copyright (C) 1998-2000 Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 2, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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-- for more details. You should have received a copy of the GNU General --
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-- Public License distributed with GNAT; see file COPYING. If not, write --
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-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
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-- MA 02111-1307, USA. --
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-- --
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-- As a special exception, if other files instantiate generics from this --
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-- unit, or you link this unit with other files to produce an executable, --
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-- this unit does not by itself cause the resulting executable to be --
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-- covered by the GNU General Public License. This exception does not --
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-- however invalidate any other reasons why the executable file might be --
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-- covered by the GNU Public License. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
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-- --
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------------------------------------------------------------------------------
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-- This is a DEC Unix 4.0d version of this package.
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-- This package contains the definitions and routines associated with the
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-- implementation of the Task_Info pragma.
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-- Note: the compiler generates direct calls to this interface, via Rtsfind.
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-- Any changes to this interface may require corresponding compiler changes.
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with Unchecked_Deallocation;
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package System.Task_Info is
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pragma Elaborate_Body;
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-- To ensure that a body is allowed
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-----------------------------------------
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-- Implementation of Task_Info Feature --
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-----------------------------------------
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-- The Task_Info pragma:
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-- pragma Task_Info (EXPRESSION);
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-- allows the specification on a task by task basis of a value of type
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-- System.Task_Info.Task_Info_Type to be passed to a task when it is
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-- created. The specification of this type, and the effect on the task
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-- that is created is target dependent.
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-- The Task_Info pragma appears within a task definition (compare the
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-- definition and implementation of pragma Priority). If no such pragma
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-- appears, then the value Task_Info_Unspecified is passed. If a pragma
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-- is present, then it supplies an alternative value. If the argument of
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-- the pragma is a discriminant reference, then the value can be set on
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-- a task by task basis by supplying the appropriate discriminant value.
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-- Note that this means that the type used for Task_Info_Type must be
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-- suitable for use as a discriminant (i.e. a scalar or access type).
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------------------
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-- Declarations --
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------------------
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type Scope_Type is
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(Process_Scope,
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-- Contend only with threads in same process
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System_Scope,
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-- Contend with all threads on same CPU
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Default_Scope);
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type Thread_Attributes is record
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Bind_To_Cpu_Number : Integer;
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-- -1: Do nothing
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-- 0: Unbind
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-- 1-N: Bind all unbound threads to this CPU
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Contention_Scope : Scope_Type;
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end record;
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type Task_Info_Type is access all Thread_Attributes;
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-- Type used for passing information to task create call, using the
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-- Task_Info pragma. This type may be specialized for individual
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-- implementations, but it must be a type that can be used as a
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-- discriminant (i.e. a scalar or access type).
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type Task_Image_Type is access String;
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-- Used to generate a meaningful identifier for tasks that are variables
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-- and components of variables.
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procedure Free_Task_Image is new
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Unchecked_Deallocation (String, Task_Image_Type);
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Unspecified_Thread_Attribute : aliased Thread_Attributes :=
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Thread_Attributes'(-1, Default_Scope);
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Unspecified_Task_Info : constant Task_Info_Type :=
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Unspecified_Thread_Attribute'Access;
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-- Value passed to task in the absence of a Task_Info pragma
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-- Don't call new here because the tasking run time has not been
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-- elaborated yet, so calling Task_Lock is unsafe.
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end System.Task_Info;
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