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function IsFileOpen(const fName: TFileName): Boolean;
var 
  HFileRes: HFILE; 
begin 
  Result := False; 
  HFileRes := CreateFile(PChar(fName),
                         GENERIC_READ or GENERIC_WRITE,
                         0,
                         nil,
                         OPEN_EXISTING, 
                         FILE_ATTRIBUTE_NORMAL, 
                         0); 
  Result := (HFileRes = INVALID_HANDLE_VALUE); 
end;


function IsFileInUse(FileName: string): boolean;
var
  TestFile: HFILE;
begin
  TestFile:=CreateFile(PChar(FileName), GENERIC_READ or GENERIC_WRITE, 0, nil,OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

  result:=TestFile=INVALID_HANDLE_VALUE;
  if not result then CloseHandle(TestFile);
end;