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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . G L O B A L _ L O C K S --
-- --
-- S p e c --
-- --
-- Copyright (C) 1999-2006, 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, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, 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. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This package contains the necessary routines to provide
-- reliable system wide locking capability.
package System.Global_Locks is
Lock_Error : exception;
-- Exception raised if a request cannot be executed on a lock
type Lock_Type is private;
-- Such a lock is a global lock between partitions. This lock is
-- uniquely defined between the partitions because of its name.
Null_Lock : constant Lock_Type;
-- This needs comments ???
procedure Create_Lock (Lock : out Lock_Type; Name : String);
-- Create or retrieve a global lock for the current partition using
-- its Name.
procedure Acquire_Lock (Lock : in out Lock_Type);
-- If the lock cannot be acquired because someone already owns it, this
-- procedure is supposed to wait and retry forever.
procedure Release_Lock (Lock : in out Lock_Type);
private
type Lock_Type is new Natural;
Null_Lock : constant Lock_Type := 0;
end System.Global_Locks;
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