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--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                  S Y S T E M . G L O B A L _ L O C K S                   --
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--                                 S p e c                                  --
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--          Copyright (C) 1999-2002 Free Software Foundation, Inc.          --
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-- GNAT is free software;  you can  redistribute it  and/or modify it under --
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-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
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-- Boston, MA 02110-1301, USA.                                              --
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--                                                                          --
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-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
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   --  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 : in 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;