From: "Steve" <nospam_steved94@attbi.com>
Subject: Re: I/O - exception handling
Date: Mon, 26 May 2003 16:31:54 GMT
Date: 2003-05-26T16:31:54+00:00 [thread overview]
Message-ID: <_jrAa.4696$_t5.1827@rwcrnsc52.ops.asp.att.net> (raw)
In-Reply-To: bat3ee$2ec$1@ns.felk.cvut.cz
Here's an approach that only uses close once, but it isn't pretty either.
begin
begin
begin
Open (File, Name => "test.txt", Mode => In_File);
exception
when others =>
null; -- report exception opening file ???
return;
end;
Get_Line (File, S1);
Get_Line (File, S2);
exception
when others =>
null; -- report exception???
end;
Close (File);
exception
when others =>
null; -- report exception ???
end Read_Something;
Steve
(The Duck)
"Sergey Koshcheyev" <serko84@hotmail.com> wrote in message
news:bat3ee$2ec$1@ns.felk.cvut.cz...
> 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.
>
>
next prev parent reply other threads:[~2003-05-26 16:31 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-26 13:05 I/O - exception handling Sergey Koshcheyev
2003-05-26 13:33 ` Preben Randhol
2003-05-26 14:11 ` Sergey Koshcheyev
2003-05-26 14:29 ` Preben Randhol
2003-05-26 14:31 ` Preben Randhol
2003-05-26 14:39 ` Sergey Koshcheyev
2003-05-26 16:57 ` Preben Randhol
2003-05-26 17:48 ` Sergey Koshcheyev
2003-05-26 18:08 ` Preben Randhol
2003-05-26 18:48 ` Sergey Koshcheyev
2003-05-27 1:24 ` Hyman Rosen
2003-05-27 2:20 ` Larry Kilgallen
2003-05-27 2:38 ` Hyman Rosen
2003-05-27 16:17 ` Warren W. Gay VE3WWG
2003-05-27 19:40 ` Hyman Rosen
2003-05-27 20:18 ` Warren W. Gay VE3WWG
2003-05-27 10:31 ` Larry Kilgallen
2003-05-27 21:43 ` Hyman Rosen
2003-05-27 5:33 ` Robert I. Eachus
2003-05-27 13:53 ` Preben Randhol
2003-05-27 12:01 ` Lutz Donnerhacke
2003-05-26 14:12 ` Simon Wright
2003-05-26 14:24 ` Preben Randhol
2003-05-26 14:52 ` Jean-Pierre Rosen
2003-05-26 15:26 ` Sergey Koshcheyev
2003-05-26 15:45 ` Hyman Rosen
2003-05-26 16:25 ` Sergey Koshcheyev
2003-05-27 1:35 ` Hyman Rosen
2003-05-28 21:47 ` Robert A Duff
2003-05-26 16:31 ` Steve [this message]
2003-05-27 2:36 ` Anisimkov
2003-05-27 7:21 ` Sergey Koshcheyev
2003-05-27 13:47 ` Preben Randhol
2003-05-27 19:01 ` Sergey Koshcheyev
2003-05-27 16:50 ` Dmitriy Anisimkov
2003-05-27 18:11 ` Ludovic Brenta
2003-05-28 1:27 ` Jeffrey Carter
2003-05-28 7:33 ` Sergey Koshcheyev
2003-05-28 9:08 ` Preben Randhol
2003-05-28 18:07 ` Randy Brukardt
2003-05-28 22:51 ` Robert I. Eachus
2003-05-29 2:03 ` Jeffrey Carter
2003-05-29 8:39 ` Manuel Collado
2003-05-30 6:56 ` Preben Randhol
2003-05-30 9:33 ` Larry Kilgallen
2003-05-30 11:13 ` Preben Randhol
2003-05-30 11:39 ` Larry Kilgallen
2003-05-30 11:41 ` Preben Randhol
2003-05-30 19:51 ` Randy Brukardt
2003-06-01 16:08 ` Robert I. Eachus
2003-06-03 0:18 ` Randy Brukardt
2003-06-03 4:16 ` Robert I. Eachus
[not found] ` <slrnbd6m69.vh.lutz@taranis.iks-jena.de>
2003-05-27 14:06 ` Preben Randhol
2003-05-27 15:59 ` Lutz Donnerhacke
2003-05-27 19:05 ` Sergey Koshcheyev
2003-05-27 19:32 ` Larry Kilgallen
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