I/O - exception handling

["Sergey Koshcheyev" <serko84@hotmail.com>]

Hi,

I have this problem: I have a simple piece of code opening a file, reading a
few lines, then closing it. Now, I want this piece of code to be "safe",
i.e. not to leak any resources (the open file) in case of errors and not to
propagate any exceptions. What is the best style to write this code?

Currently, I have something like (not compiled):

procedure Read_Something (...) is
   use Ada.Text_IO;
   use Ada.Strings.Unbounded;
   use Ada.Strings.Unbounded.Text_IO;
   --  GNAT-specific package, I believe

   File : File_Type;
   S1, S2 : Unbounded_String;

begin
   Open (File, Name => "test.txt", Mode => In_File);
   Get_Line (File, S1);
   Get_Line (File, S2);
   Close (File);

exception
   when others =>
      if Is_Open (File) then
         begin
            Close (File);
         exception
            --  Close can raise exceptions too!
            when others => null;
         end;
      end if;
end Read_Something;

However, this looks ugly to me, since I have to close the file in two
places, and also guard for exceptions while handling exceptions. Is there a
better solution or is this sort of thing OK in the Ada way?

Sergey.