| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 1999-2002 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. -- |
| -- 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 : 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; |
