Unlock locked file after systemcrash

Hi,

I want to build a very basic File-Unlock application that will unlock a specific file that remains locked after unexpected closing of my application (f.e. after a systemcrash). It should support commandline possibilities.

Here is why:
To make sure only one user is allowed to have access to my application I use a locked file method (see code part).

But when the system crashes or my app runs into a unexpected error, this file might remain locked. Therefor I want to allow a user to unlock the file, so he can get access to the application again.

{Two application that do what I want are Unpacker and FileAssassin. But these applications must be installed on the enduser's computer, therefor I would rather build it into my own application. I you know of any commandprompt application that will do it all for me, than that is fine for me too.}

Can anybody give me a small sample on how to get this working?

// Added to the source of the application
var vFileStream : TFileStream;
 
begin
  try
    vFileStream := TFileStream.Create( ExtractFilePath(Application.ExeName) + 'InUse.fil',fmCreate or fmShareExclusive);
  except
    MessageDlg('Program is already in use.', mtInformation, [mbOK], 0);
    Exit;
  end;
  Application.Initialize;
  ETC....
end;

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