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From: Tim Wright <timw@splhi.com>
To: Paul Jackson <pj@sgi.com>
Cc: Eyal Lebedinsky <eyal@eyal.emu.id.au>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Use NULL instead of integer 0 in security/selinux/
Date: Sat, 10 Jul 2004 17:12:43 -0700	[thread overview]
Message-ID: <1089504763.1473.28.camel@tp-timw.internal.splhi.com> (raw)
In-Reply-To: <20040710165207.477efad6.pj@sgi.com>

It was because

if (0 = i)

will give an error where you obviously meant '=='. It prevents
accidental "assignment in conditional context".

Tim

On Sat, 2004-07-10 at 16:52, Paul Jackson wrote:
> (off-topic alert)
> 
> >	if (0 != i)
> 
> Does anyone know of the origins of writing such tests this way, rather
> than:
> 
> 	if (i != 0)
> 
> I read the first as testing whether "0" has a certain property, which is
> a silly thing to test, since the properties of "0" are rather constant.
> 
> The second form I read as testing a property of "i" - much more
> interesting.  Logically, the same, of course.  Just a question of which
> form is more idiomatic.
> 
> Back in the days when it was Ken, Dennis and Brian, not K & R, I don't
> recall seeing the first form used much.  Even now I see _zero_ matches
> on "if (0 " in kernel or mm - only in arch, drivers, net, scripts, and
> sound (with a single time.h exception).
> 
> If I were Linus, I'd vote the first form off the island.  Then again,
> if I were Linus, you would never have heard of Linux ;).

  reply	other threads:[~2004-07-11  0:14 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-07-07 19:25 [PATCH] Use NULL instead of integer 0 in security/selinux/ Chris Wright
2004-07-08  3:12 ` Herbert Xu
2004-07-08  3:27   ` David S. Miller
2004-07-08  3:43     ` Miles Bader
2004-07-08  5:22       ` Linus Torvalds
2004-07-08  5:35         ` Miles Bader
2004-07-08 15:58           ` Linus Torvalds
2004-07-08 16:23             ` Dave Jones
2004-07-08 17:57               ` Geert Uytterhoeven
2004-07-09 11:23             ` Roman Zippel
2004-07-10 19:41               ` Geert Uytterhoeven
2004-07-11 10:29                 ` Geert Uytterhoeven
2004-07-11 10:54                   ` viro
2004-07-11 16:14                   ` Linus Torvalds
2004-07-11 20:05                 ` H. Peter Anvin
2004-07-12 15:58                   ` Florian Weimer
2004-07-12 16:34                     ` H. Peter Anvin
2004-07-08 11:18         ` Herbert Xu
2004-07-08 13:10           ` Andreas Schwab
2004-07-08 13:56             ` Herbert Xu
2004-07-08 14:13               ` Andreas Schwab
2004-07-08  5:19   ` Linus Torvalds
2004-07-08 16:09     ` Timothy Miller
2004-07-08 16:21       ` Linus Torvalds
2004-07-08 16:27         ` Linus Torvalds
2004-07-08 16:52         ` Timothy Miller
     [not found]           ` <200407090056.51084.vda@port.imtp.ilyichevsk.odessa.ua>
2004-07-12 15:17             ` Timothy Miller
2004-07-12 16:12               ` Andreas Schwab
2004-07-12 16:51                 ` Andrew Pimlott
2004-07-15 16:15                 ` Timothy Miller
2004-07-09 20:36     ` Eric W. Biederman
2004-07-09 23:49       ` Paul Jackson
2004-07-10  1:43         ` Kyle Moffett
2004-07-10  1:47           ` Herbert Xu
2004-07-10 21:53             ` Alexandre Oliva
2004-07-10  6:18       ` Linus Torvalds
2004-07-10  6:23         ` Linus Torvalds
2004-07-10  6:58           ` Andrea Arcangeli
2004-07-10  9:48             ` Eric W. Biederman
2004-07-10 15:39           ` Roland Dreier
2004-07-11  2:45             ` Eyal Lebedinsky
2004-07-11 21:19             ` Olaf Titz
2004-07-10  9:39         ` Eric W. Biederman
2004-07-10  9:56           ` Herbert Xu
2004-07-11 21:47           ` Olaf Titz
2004-07-13  8:43             ` Geert Uytterhoeven
2004-07-14  3:12               ` Alexandre Oliva
2004-07-13 18:53             ` Elladan
2004-07-14  3:15             ` Alexandre Oliva
2004-07-10 12:11         ` Roman Zippel
2004-07-10 21:59         ` Alexandre Oliva
2004-07-11  4:40           ` Linus Torvalds
2004-07-10  9:31       ` Eyal Lebedinsky
2004-07-10 22:07         ` Alexandre Oliva
2004-07-10 23:52         ` Paul Jackson
2004-07-11  0:12           ` Tim Wright [this message]
2004-07-12 22:03       ` Bill Davidsen
2004-07-10  8:18     ` Florian Weimer
2004-07-08 11:10   ` Richard B. Johnson
2004-07-08 11:28     ` Michael Buesch
2004-07-08 11:44       ` Martin Zwickel
2004-07-08 12:06         ` Michael Buesch
2004-07-08 12:38           ` [OT] NULL versus 0 (Re: [PATCH] Use NULL instead of integer 0 in security/selinux/) Kari Hurtta
2004-07-08 12:42             ` Michael Buesch
2004-07-08 12:57               ` Kari Hurtta
2004-07-08 15:25                 ` Herbert Xu
2004-07-10  8:22           ` [PATCH] Use NULL instead of integer 0 in security/selinux/ Florian Weimer
2004-07-08 11:43     ` P. Benie
2004-07-08 14:32       ` Richard B. Johnson
2004-07-08 15:00         ` Michael Poole
2004-07-08 15:30           ` P. Benie
2004-07-08 15:55           ` Andreas Schwab
2004-07-10  7:09         ` Andrea Arcangeli
2004-07-10  7:02       ` Andrea Arcangeli
2004-07-10  6:59     ` Andrea Arcangeli

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