------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- G N A T . L O C K _ F I L E S -- -- -- -- S p e c -- -- -- -- Copyright (C) 1995-2010, AdaCore -- -- -- -- 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 -- -- . -- -- -- -- 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 for using files for the -- purpose of providing reliable system wide locking capability. package GNAT.Lock_Files is pragma Preelaborate; Lock_Error : exception; -- Exception raised if file cannot be locked subtype Path_Name is String; -- Pathname is used by all services provided in this unit to specified -- directory name and file name. On DOS based systems both directory -- separators are handled (i.e. slash and backslash). procedure Lock_File (Directory : Path_Name; Lock_File_Name : Path_Name; Wait : Duration := 1.0; Retries : Natural := Natural'Last); -- Create a lock file Lock_File_Name in directory Directory. If the file -- cannot be locked because someone already owns the lock, this procedure -- waits Wait seconds and retries at most Retries times. If the file -- still cannot be locked, Lock_Error is raised. The default is to try -- every second, almost forever (Natural'Last times). The full path of -- the file is constructed by concatenating Directory and Lock_File_Name. -- Directory can optionally terminate with a directory separator. procedure Lock_File (Lock_File_Name : Path_Name; Wait : Duration := 1.0; Retries : Natural := Natural'Last); -- See above. The full lock file path is given as one string procedure Unlock_File (Directory : Path_Name; Lock_File_Name : Path_Name); -- Unlock a file. Directory can optionally terminate with a directory -- separator. procedure Unlock_File (Lock_File_Name : Path_Name); -- Unlock a file whose full path is given in Lock_File_Name end GNAT.Lock_Files;