From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: new_line in a put_line
Date: Mon, 2 Dec 2002 15:49:29 GMT
Date: 2002-12-02T15:49:29+00:00 [thread overview]
Message-ID: <wcc7kesqv3q.fsf@shell01.TheWorld.com> (raw)
In-Reply-To: aserlb$juh$1@fang.dsto.defence.gov.au
"Vlad" <vbednikov@optusnet.com.au> writes:
> Is there a way of prepending a new_line to a put_line.
> The reason I need this is that I have multiple tasks outputing to a\
> single file. Some of them use Text_IO.Put rather then Text_IO.Put_Line.
> And because of this, some of these outputs get written on the same line
> as my outputs.
You seem to be assuming that each call to Put or Put_Line is atomic.
That's not true, so inserting a new-line into the string passed to
Put_Line is not a correct solution.
If one task says:
Put_Line("Hello");
and another task simultaneously says:
Put_Line("Goodbye");
the program is erroneous, which means it can have totally unpredictable
behavior. It might intersperse the characters, so you get:
HelGoodl
obye
or it might print what you want:
Hello
Goodbye
or it might crash, or anything else.
What you need to do is synchronize your accesses to the standard output
file, perhaps using a protected object.
- Bob
next prev parent reply other threads:[~2002-12-02 15:49 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-12-02 5:36 new_line in a put_line Vlad
2002-12-02 9:47 ` Preben Randhol
2002-12-02 17:04 ` Frank J. Lhota
2002-12-05 11:10 ` Preben Randhol
2002-12-02 10:14 ` Dmitry A. Kazakov
2002-12-02 14:57 ` Matthew Heaney
2002-12-03 11:33 ` Fraser Wilson
2002-12-03 15:01 ` Dmitry A. Kazakov
2002-12-04 9:31 ` Fraser Wilson
2002-12-04 14:10 ` Dmitry A. Kazakov
2002-12-04 15:23 ` Robert A Duff
2002-12-04 16:15 ` Dmitry A. Kazakov
2002-12-04 18:11 ` tmoran
2002-12-04 20:21 ` Simon Wright
2002-12-05 9:36 ` Dmitry A. Kazakov
2002-12-05 22:40 ` tmoran
2002-12-04 15:25 ` Stephen Leake
2002-12-04 16:55 ` Jeffrey Carter
2002-12-04 17:24 ` Stephen Leake
2002-12-04 17:43 ` Warren W. Gay VE3WWG
2002-12-05 1:31 ` Jeffrey Carter
2002-12-05 18:11 ` Warren W. Gay VE3WWG
2002-12-02 15:49 ` Robert A Duff [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-12-03 11:52 Grein, Christoph
2002-12-04 9:39 ` Fraser Wilson
2002-12-04 10:03 Grein, Christoph
2002-12-05 6:16 Grein, Christoph
2002-12-05 9:44 ` Dmitry A. Kazakov
2002-12-05 6:28 Grein, Christoph
2002-12-05 14:19 ` Stephen Leake
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