| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 1999-2021, 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 3, 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. -- |
| -- -- |
| -- As a special exception under Section 7 of GPL version 3, you are granted -- |
| -- additional permissions described in the GCC Runtime Library Exception, -- |
| -- version 3.1, as published by the Free Software Foundation. -- |
| -- -- |
| -- You should have received a copy of the GNU General Public License and -- |
| -- a copy of the GCC Runtime Library Exception along with this program; -- |
| -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- |
| -- <http://www.gnu.org/licenses/>. -- |
| -- -- |
| -- 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; |
