From: Maciej Sobczak <see.my.homepage@gmail.com>
Subject: Re: for S'Image use Func??
Date: Tue, 11 May 2010 00:58:16 -0700 (PDT)
Date: 2010-05-11T00:58:16-07:00 [thread overview]
Message-ID: <ffdf209e-dbc3-484a-94b0-b9630a69aaa1@g21g2000yqk.googlegroups.com> (raw)
In-Reply-To: op.vcigjcwmxmjfy8@garhos
On 11 Maj, 00:24, Yannick Duchêne (Hibou57) <yannick_duch...@yahoo.fr>
wrote:
> Only as long as you only rely on fopen ;
This function is defined in the C standard.
> there is also an "int open(char *
> filename, int flags)" which is widely used.
This one is not defined in the C standard and as such is not part of
the C language.
> Weither or not this "int"
> actually stands for a pointer is another story (as in C one will always be
> able to cast from int to void*, this may be true indeed).
No this is not true either - assuming that you mean the "open"
function defined in the POSIX standard, the return value is the lowest
*numbered* unused file descriptor. This is aligned with the semantics
of other functions like select.
Another reason for why this cannot be a pointer is that NULL is
defined to be a pointer value that does *not* point to any object; at
the same time STDIN_FILENO, denoting a file descriptor for standard
input, has a value 0, which is equivalent to NULL.
Since standard input cannot exist and not exist at the same time
(quantum computers might change this...), the descriptor value cannot
be a pointer.
Interestingly, Unix file descriptors are *much safer* than standard
C's FILE pointers in that they are free from undefined behavior. Of
course, it would be even better to have a distinct type for them.
(OK, that's enough for off-topic confusions, I duck away to reinvent
My_Better.Text_IO on top of Ada.Streams ;-) )
--
Maciej Sobczak * http://www.inspirel.com
YAMI4 - Messaging Solution for Distributed Systems
http://www.inspirel.com/yami4
next prev parent reply other threads:[~2010-05-11 7:58 UTC|newest]
Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-06 17:10 for S'Image use Func?? Warren
2010-05-06 17:23 ` Dmitry A. Kazakov
2010-05-06 20:05 ` Warren
2010-05-06 17:58 ` Adam Beneschan
2010-05-06 19:52 ` Warren
2010-05-07 8:12 ` stefan-lucks
2010-05-08 5:26 ` Stephen Leake
2010-05-10 15:16 ` Charmed Snark
2010-05-07 2:10 ` Randy Brukardt
2010-05-07 18:24 ` Keith Thompson
2010-05-06 18:14 ` Yannick Duchêne (Hibou57)
2010-05-06 20:04 ` Warren
2010-05-06 20:19 ` Robert A Duff
2010-05-06 20:56 ` Yannick Duchêne (Hibou57)
2010-05-06 21:11 ` Robert A Duff
2010-05-07 8:40 ` J-P. Rosen
2010-05-07 12:21 ` Robert A Duff
2010-05-07 13:37 ` Georg Bauhaus
2010-05-07 14:25 ` Robert A Duff
2010-05-07 15:46 ` Yannick Duchêne (Hibou57)
2010-05-07 17:38 ` Dmitry A. Kazakov
2010-05-07 20:15 ` Yannick Duchêne (Hibou57)
2010-05-07 20:28 ` Jeffrey R. Carter
2010-05-07 21:16 ` Randy Brukardt
2010-05-07 22:18 ` Jeffrey R. Carter
2010-05-09 0:06 ` Randy Brukardt
2010-05-09 0:31 ` Jeffrey R. Carter
2010-05-07 20:31 ` Robert A Duff
2010-05-07 20:51 ` Yannick Duchêne (Hibou57)
2010-05-07 21:07 ` Robert A Duff
2010-05-07 21:25 ` Randy Brukardt
2010-05-07 22:16 ` Jeffrey R. Carter
2010-05-10 15:48 ` Warren
2010-05-10 16:31 ` Dmitry A. Kazakov
2010-05-10 16:52 ` Warren
2010-05-10 17:55 ` Dmitry A. Kazakov
2010-05-10 18:50 ` Warren
2010-05-10 19:20 ` Niklas Holsti
2010-05-10 20:16 ` Warren
2010-05-10 20:38 ` Simon Wright
2010-05-10 20:52 ` Warren
2010-05-11 17:38 ` Jeffrey R. Carter
2010-05-11 18:19 ` Yannick Duchêne (Hibou57)
2010-05-11 20:36 ` Warren
2010-05-11 7:34 ` Niklas Holsti
2010-05-11 7:56 ` Yannick Duchêne (Hibou57)
2010-05-11 16:56 ` Warren
2010-05-13 18:53 ` Niklas Holsti
2010-05-11 16:49 ` Warren
2010-05-11 8:26 ` Dmitry A. Kazakov
2010-05-11 9:49 ` J-P. Rosen
2010-05-11 17:06 ` Warren
2010-05-12 5:00 ` J-P. Rosen
2010-05-12 14:39 ` Yannick Duchêne (Hibou57)
2010-05-12 16:52 ` Warren
2010-05-13 18:20 ` Niklas Holsti
2010-05-17 10:00 ` J-P. Rosen
2010-05-20 9:31 ` Niklas Holsti
2010-05-21 6:56 ` Niklas Holsti
2010-05-11 14:27 ` Robert A Duff
2010-05-11 15:03 ` Dmitry A. Kazakov
2010-05-11 15:45 ` Yannick Duchêne (Hibou57)
2010-05-11 15:23 ` Yannick Duchêne (Hibou57)
2010-05-11 16:59 ` Dmitry A. Kazakov
2010-05-11 17:05 ` Warren
2010-05-11 17:54 ` Dmitry A. Kazakov
2010-05-11 20:50 ` Charmed Snark
2010-05-11 19:03 ` Yannick Duchêne (Hibou57)
2010-05-11 20:53 ` Warren
2010-05-10 20:56 ` Maciej Sobczak
2010-05-10 20:24 ` Georg Bauhaus
2010-05-11 7:42 ` Maciej Sobczak
2010-05-10 21:30 ` Ludovic Brenta
2010-05-11 8:35 ` Dmitry A. Kazakov
2010-05-11 13:35 ` Maciej Sobczak
2010-05-11 14:24 ` Dmitry A. Kazakov
2010-05-11 20:18 ` Maciej Sobczak
2010-05-11 21:46 ` Dmitry A. Kazakov
2010-05-12 13:16 ` Maciej Sobczak
2010-05-12 14:33 ` Yannick Duchêne (Hibou57)
2010-05-12 15:58 ` Dmitry A. Kazakov
2010-05-12 22:14 ` Maciej Sobczak
2010-05-13 7:31 ` Dmitry A. Kazakov
2010-05-13 13:16 ` Warren
2010-05-14 21:03 ` Maciej Sobczak
2010-05-15 8:35 ` Dmitry A. Kazakov
2010-05-15 20:50 ` Maciej Sobczak
2010-05-16 7:48 ` Dmitry A. Kazakov
2010-05-16 20:56 ` Maciej Sobczak
2010-05-16 21:31 ` Dmitry A. Kazakov
2010-05-11 15:56 ` Yannick Duchêne (Hibou57)
2010-05-11 17:15 ` Dmitry A. Kazakov
2010-05-11 18:48 ` Yannick Duchêne (Hibou57)
2010-05-10 22:24 ` Yannick Duchêne (Hibou57)
2010-05-11 7:58 ` Maciej Sobczak [this message]
2010-05-11 15:54 ` Yannick Duchêne (Hibou57)
2010-05-11 20:23 ` Maciej Sobczak
2010-05-10 22:39 ` Yannick Duchêne (Hibou57)
2010-05-11 17:17 ` Warren
2010-05-11 17:59 ` Dmitry A. Kazakov
2010-05-11 20:56 ` Warren
2010-05-11 22:06 ` Dmitry A. Kazakov
2010-05-12 13:27 ` Warren
2010-05-12 16:03 ` Dmitry A. Kazakov
2010-05-11 18:57 ` Yannick Duchêne (Hibou57)
2010-05-11 21:08 ` Warren
2010-05-11 19:56 ` Gautier write-only
2010-05-12 13:33 ` Warren
2010-05-07 15:35 ` Yannick Duchêne (Hibou57)
2010-05-07 20:33 ` Robert A Duff
2010-05-07 21:27 ` Randy Brukardt
2010-05-07 21:36 ` Robert A Duff
2010-05-07 22:09 ` Yannick Duchêne (Hibou57)
2010-05-09 0:17 ` Randy Brukardt
2010-05-07 19:56 ` J-P. Rosen
2010-05-07 20:14 ` Robert A Duff
2010-05-07 20:17 ` Yannick Duchêne (Hibou57)
2010-05-07 20:41 ` Robert A Duff
2010-05-06 21:20 ` Dmitry A. Kazakov
2010-05-10 15:26 ` Ada & gdb (was: for S'Image use Func??) Warren
2010-05-10 18:02 ` John B. Matthews
2010-05-10 19:52 ` Warren
2010-05-06 22:33 ` for S'Image use Func?? Jeffrey R. Carter
2010-05-06 23:22 ` Yannick Duchêne (Hibou57)
2010-05-07 2:17 ` Randy Brukardt
2010-05-07 12:27 ` Robert A Duff
2010-05-07 15:19 ` Yannick Duchêne (Hibou57)
2010-05-07 20:19 ` Robert A Duff
2010-05-07 21:11 ` Randy Brukardt
2010-05-10 16:05 ` Warren
2010-05-19 6:26 ` Randy Brukardt
2010-05-07 15:21 ` Yannick Duchêne (Hibou57)
2010-05-10 16:03 ` Warren
2010-05-06 18:50 ` Jeffrey R. Carter
2010-05-06 19:50 ` Warren
2010-05-06 20:22 ` Robert A Duff
2010-05-06 21:25 ` Dmitry A. Kazakov
2010-05-07 2:20 ` Randy Brukardt
2010-05-07 7:28 ` Dmitry A. Kazakov
2010-05-07 10:15 ` Stephen Leake
2010-05-07 15:07 ` Yannick Duchêne (Hibou57)
2010-05-08 5:38 ` Stephen Leake
2010-05-07 19:29 ` Simon Wright
2010-05-07 20:10 ` Robert A Duff
2010-05-07 19:44 ` Georg Bauhaus
2010-05-07 20:53 ` Robert A Duff
2010-05-07 21:59 ` Simon Wright
2010-05-09 0:20 ` Randy Brukardt
2010-05-07 8:53 ` Georg Bauhaus
2010-05-10 16:18 ` Warren
2010-05-10 17:54 ` Georg Bauhaus
2010-05-10 19:57 ` Warren
2010-05-10 19:09 ` Yannick Duchêne (Hibou57)
2010-05-10 20:01 ` Warren
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