From: Maciej Sobczak <no.spam@no.spam.com>
Subject: Get_Line problem (GNAT bug?)
Date: Wed, 06 Dec 2006 15:25:31 +0100
Date: 2006-12-06T15:25:31+01:00 [thread overview]
Message-ID: <el6jss$268$1@cernne03.cern.ch> (raw)
Hi,
Consider:
with Ada.Text_IO;
procedure Hello is
use Ada.Text_IO;
Input_Line : String(1..100);
Last_Index : Integer range 0..100;
begin
loop
Put("What's your name? ");
exit when End_Of_File;
Get_Line(Input_Line, Last_Index);
if Last_Index >= Input_Line'First then
Put("Hi, ");
Put(Input_Line(1..Last_Index));
New_Line;
else
Put("You have funny empty name.");
New_Line;
end if;
end loop;
end Hello;
(please focus on the Get_Line problem here)
It should be obvious what the program does, except that the behaviour in
the case of empty input line is a bit strange.
Below, in the right-hand column I describe what keys were pressed:
$ ./hello
What's your name? Maciek -- M a c i e k ENTER
Hi, Maciek
What's your name? -- ENTER
-- ENTER
You have funny empty name.
What's your name? -- ENTER
You have funny empty name.
What's your name? -- EOF
$
As you see, the first ENTER was somehow "swollowed", creating an empty
line in the console (that's the echo of what user typed), but still
blocking in Get_Line. All subsequent ENTERs seem to be handled
correctly, which means that Get_Line returns with Last_Index <
Input_Line'First.
I was already suggested that it might be a GNAT feature. If yes, it
seems to be persistent, because I see it with two different versions.
Of course, I expect that empty lines are handled uniformly.
Any thoughts?
--
Maciej Sobczak : http://www.msobczak.com/
Programming : http://www.msobczak.com/prog/
next reply other threads:[~2006-12-06 14:25 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-06 14:25 Maciej Sobczak [this message]
2006-12-06 18:06 ` Get_Line problem (GNAT bug?) Adam Beneschan
2006-12-06 20:34 ` Gautier
2006-12-06 21:47 ` Dmitry A. Kazakov
2006-12-06 23:40 ` Adam Beneschan
2006-12-07 0:02 ` Björn Persson
2006-12-07 1:09 ` Adam Beneschan
2006-12-07 1:28 ` Björn Persson
2006-12-07 5:00 ` Jeffrey R. Carter
2006-12-07 8:26 ` Maciej Sobczak
2006-12-07 9:21 ` Jean-Pierre Rosen
2006-12-07 13:35 ` Ludovic Brenta
2006-12-07 22:23 ` Robert A Duff
2006-12-07 10:22 ` Dmitry A. Kazakov
2006-12-07 14:51 ` Maciej Sobczak
2006-12-07 16:29 ` Dmitry A. Kazakov
2006-12-08 8:22 ` Maciej Sobczak
2006-12-07 22:50 ` Robert A Duff
2006-12-08 0:13 ` Randy Brukardt
2006-12-08 4:04 ` Larry Kilgallen
2006-12-08 9:11 ` Dmitry A. Kazakov
2006-12-07 9:14 ` Jean-Pierre Rosen
2006-12-07 3:34 ` Steve
2006-12-07 17:42 ` Adam Beneschan
2006-12-07 22:35 ` Robert A Duff
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