gcc/ada/s-gloloc.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                  S Y S T E M . G L O B A L _ L O C K S                   --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1999-2006, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34    --  This package contains the necessary routines to provide
  35    --  reliable system wide locking capability.
  36
  37 package System.Global_Locks is
  38
  39    Lock_Error : exception;
  40    --  Exception raised if a request cannot be executed on a lock
  41
  42    type Lock_Type is private;
  43    --  Such a lock is a global lock between partitions. This lock is
  44    --  uniquely defined between the partitions because of its name.
  45
  46    Null_Lock : constant Lock_Type;
  47    --  This needs comments ???
  48
  49    procedure Create_Lock (Lock : out Lock_Type; Name : String);
  50    --  Create or retrieve a global lock for the current partition using
  51    --  its Name.
  52
  53    procedure Acquire_Lock (Lock : in out Lock_Type);
  54    --  If the lock cannot be acquired because someone already owns it, this
  55    --  procedure is supposed to wait and retry forever.
  56
  57    procedure Release_Lock (Lock : in out Lock_Type);
  58
  59 private
  60
  61    type Lock_Type is new Natural;
  62
  63    Null_Lock : constant Lock_Type := 0;
  64
  65 end System.Global_Locks;