gcc/ada/g-locfil.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                      G N A T . L O C K _ F I L E S                       --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --                     Copyright (C) 1995-2010, AdaCore                     --
  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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 --  This package contains the necessary routines for using files for the
  33 --  purpose of providing reliable system wide locking capability.
  34
  35 package GNAT.Lock_Files is
  36    pragma Preelaborate;
  37
  38    Lock_Error : exception;
  39    --  Exception raised if file cannot be locked
  40
  41    subtype Path_Name is String;
  42    --  Pathname is used by all services provided in this unit to specified
  43    --  directory name and file name. On DOS based systems both directory
  44    --  separators are handled (i.e. slash and backslash).
  45
  46    procedure Lock_File
  47      (Directory      : Path_Name;
  48       Lock_File_Name : Path_Name;
  49       Wait           : Duration := 1.0;
  50       Retries        : Natural  := Natural'Last);
  51    --  Create a lock file Lock_File_Name in directory Directory. If the file
  52    --  cannot be locked because someone already owns the lock, this procedure
  53    --  waits Wait seconds and retries at most Retries times. If the file
  54    --  still cannot be locked, Lock_Error is raised. The default is to try
  55    --  every second, almost forever (Natural'Last times). The full path of
  56    --  the file is constructed by concatenating Directory and Lock_File_Name.
  57    --  Directory can optionally terminate with a directory separator.
  58
  59    procedure Lock_File
  60      (Lock_File_Name : Path_Name;
  61       Wait           : Duration := 1.0;
  62       Retries        : Natural  := Natural'Last);
  63    --  See above. The full lock file path is given as one string
  64
  65    procedure Unlock_File (Directory : Path_Name; Lock_File_Name : Path_Name);
  66    --  Unlock a file. Directory can optionally terminate with a directory
  67    --  separator.
  68
  69    procedure Unlock_File (Lock_File_Name : Path_Name);
  70    --  Unlock a file whose full path is given in Lock_File_Name
  71
  72 end GNAT.Lock_Files;