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------------------------------------------------------------------------------
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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 . G L O B A L _ L O C K S --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1999-2002 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, 51 Franklin Street, Fifth Floor, --
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-- Boston, MA 02110-1301, 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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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This package contains the necessary routines to provide
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-- reliable system wide locking capability.
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package System.Global_Locks is
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Lock_Error : exception;
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-- Exception raised if a request cannot be executed on a lock.
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type Lock_Type is private;
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-- Such a lock is a global lock between partitions. This lock is
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-- uniquely defined between the partitions because of its name.
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Null_Lock : constant Lock_Type;
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-- This needs comments ???
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procedure Create_Lock (Lock : out Lock_Type; Name : in String);
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-- Create or retrieve a global lock for the current partition using
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-- its Name.
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procedure Acquire_Lock (Lock : in out Lock_Type);
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-- If the lock cannot be acquired because someone already owns it, this
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-- procedure is supposed to wait and retry forever.
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procedure Release_Lock (Lock : in out Lock_Type);
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private
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type Lock_Type is new Natural;
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Null_Lock : constant Lock_Type := 0;
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end System.Global_Locks;
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