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From: "Shorty Porty" <getshorty_@hotmail.com>
To: <linux-kernel@vger.kernel.org>
Cc: <ricknu-0@student.ltu.se>
Subject: RE: [RFC][PATCH] A generic boolean
Date: Thu, 20 Jul 2006 13:53:27 +1000	[thread overview]
Message-ID: <BAY104-DAV11BD5C0159C7CD7BA10CA3ED610@phx.gbl> (raw)
In-Reply-To: <Pine.LNX.4.58.0607192003030.20069@shell3.speakeasy.net>

Someone showed code like

  _Bool foo = 42;

and if we were to make the compiler warn about it that would mean we are
basically trying to change/manipulate the standard (I'm guessing). It's
probably not in the standard because it's such a moot point. However if we
were to use

  if(foo)
  {
    ...
  }

we'd see it was true. That's because 
  FALSE == 0
and
  TRUE == !FALSE (i.e. any value that isn't 0)

from the compiler's standpoint. Function that return 'true' for an integer
type (as opposed to a C++ standard-type bool) should be tested like

  if(SomeFunction())

or
  if(!SomeFunction())

instead of testing for equality

  if(SomeFunction() == TRUE)
of
  if(SomeFunction() == FALSE)

as the former (IMO) is as readable, if not more readable as the latter, and
it's likely to get optimised better. That and someone might give true AND
return a status by returning neither 0 or 1, in which case 

  if(... == TRUE)

would fail, as TRUE == 1.

And just as a note, you really should read the documentation (at least once)
for any function you use, and therefore know if it returns {FALSE, TRUE, ...
, TRUE} or {OK, ERR1, ERR2, ..., ERRn}

> > If this is the case, then wouldn't "long" be preferable to "int"?

Meh, it's all the same. I don't think 3 wasted CPU cycles is going to worry
anyone too much. Hell, sometimes int IS long, though I might be wrong there.


P.S. First post! Hello everybody.

  reply	other threads:[~2006-07-20  3:46 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-07-19 20:38 ricknu-0
2006-07-19 21:04 ` Jeff Garzik
2006-07-19 23:17   ` ricknu-0
2006-07-20  0:13     ` Jeff Garzik
2006-07-20  3:04       ` Vadim Lobanov
2006-07-20  3:53         ` Shorty Porty [this message]
2006-07-20  3:59           ` Dmitry Torokhov
2006-07-20  8:07           ` Jan Engelhardt
2006-08-04 14:03   ` Jes Sorensen
2006-08-04 14:42     ` Alan Cox
2006-08-04 14:35       ` Jes Sorensen
2006-08-04 15:51         ` Alan Cox
2006-08-04 15:58           ` Jes Sorensen
2006-08-04 16:00             ` Andreas Schwab
2006-08-04 16:08               ` Jes Sorensen
2006-08-04 16:16                 ` Andreas Schwab
2006-08-04 16:26                   ` Jes Sorensen
2006-08-04 16:57                     ` Andreas Schwab
2006-08-04 18:47                       ` Jes Sorensen
2006-08-04 18:51                         ` H. Peter Anvin
2006-08-04 18:58                           ` Jes Sorensen
2006-08-04 19:04                             ` H. Peter Anvin
2006-08-06  9:25                   ` Jan Engelhardt
2006-08-06  9:48                     ` Andreas Schwab
2006-08-06  9:31                 ` Jan Engelhardt
2006-08-06 15:31                   ` Jes Sorensen
2006-08-04 16:30             ` Alan Cox
2006-08-04 16:20               ` Jes Sorensen
2006-07-19 21:20 ` Alexey Dobriyan
2006-07-19 22:47   ` ricknu-0
2006-07-19 23:52     ` Peter Williams
2006-07-20  0:08       ` ricknu-0
2006-07-20  8:09   ` Jan Engelhardt
2006-07-21  1:24 ` [RFC][PATCH] A generic boolean (version 2) ricknu-0
2006-07-21  1:34   ` Jeff Garzik
2006-07-21  8:55     ` Pekka Enberg
2006-07-21 21:14       ` Jeff Garzik
2006-07-25 19:04         ` Roman Kononov
2006-07-21 22:31     ` ricknu-0
2006-07-23 19:56     ` ricknu-0
2006-07-21 14:23   ` Jan Engelhardt
2006-07-21 18:27     ` Michael Buesch
2006-07-21 21:14       ` Jeff Garzik
2006-07-21 22:11         ` ricknu-0
2006-07-22  8:56       ` Jan Engelhardt
2006-07-21 23:08 ` [RFC][PATCH] A generic boolean (version 3) ricknu-0
2006-07-21 23:27 ` ricknu-0
2006-07-22  5:40   ` Stefan Richter
2006-07-22 17:08     ` ricknu-0
2006-07-22 18:08       ` Stefan Richter
2006-07-22  8:58   ` Jan Engelhardt
2006-07-22 17:19     ` ricknu-0
2006-07-22  9:55   ` Lars Gullik Bjønnes
2006-07-23 15:43     ` ricknu-0
2006-07-23 15:49 ` [RFC][PATCH] A generic boolean (version 4) ricknu-0
2006-07-23 16:08   ` Jan Engelhardt
2006-07-23 19:36     ` ricknu-0
2006-07-23 20:26       ` Jeff Garzik
2006-07-23 20:25     ` Jeff Garzik
2006-07-23 21:17       ` Jan Engelhardt
2006-07-23 21:44         ` Jeff Garzik
2006-07-24  8:55     ` Paul Jackson
2006-07-23 16:13   ` Michael Buesch
2006-07-23 19:46     ` ricknu-0
2006-07-23 20:24   ` Jeff Garzik
2006-07-23 21:13   ` Paul Jackson
2006-07-25 23:22 ` [RFC][PATCH] A generic boolean (version 5) ricknu-0
2006-07-26  0:42   ` Paul Jackson
2006-07-26 20:28 ` [RFC][PATCH] A generic boolean (version 6) ricknu-0
2006-07-27  1:06   ` Paul Jackson
2006-07-27  2:10     ` Josef Sipek
2006-07-27  3:51       ` ricknu-0
2006-07-27  4:40         ` Josef Sipek
2006-07-27  4:00       ` Paul Jackson
2006-07-27  3:30     ` ricknu-0
2006-07-28 16:57     ` Jan Engelhardt
2006-07-27  2:48   ` Arnd Bergmann
2006-07-27  3:22     ` ricknu-0
2006-07-27  5:27     ` Nicholas Miell
2006-07-27  6:51       ` Paul Jackson
2006-07-27 19:55       ` ricknu-0
2006-07-27 20:13         ` Nicholas Miell
2006-07-28  1:29           ` ricknu-0
2006-07-28  1:56             ` Nicholas Miell
2006-07-28 12:50           ` Alan Cox
2006-07-28 20:24             ` Lars Noschinski
2006-07-28 21:31               ` Nicholas Miell
2006-07-27 19:46 ` [RFC][PATCH] A generic boolean (version 7) ricknu-0
     [not found] <6AqZX-3dU-29@gated-at.bofh.it>
     [not found] ` <6Art3-45j-35@gated-at.bofh.it>
     [not found]   ` <6G8xj-W7-13@gated-at.bofh.it>
     [not found]     ` <6G8QL-1lI-35@gated-at.bofh.it>
     [not found]       ` <6G90s-1yo-55@gated-at.bofh.it>
     [not found]         ` <6G9Wm-30t-3@gated-at.bofh.it>
     [not found]           ` <6GafR-3o1-13@gated-at.bofh.it>
     [not found]             ` <6Gapq-3OH-15@gated-at.bofh.it>
     [not found]               ` <6Gapq-3OH-13@gated-at.bofh.it>
     [not found]                 ` <6Gaz6-40T-21@gated-at.bofh.it>
     [not found]                   ` <6GaIN-4dw-25@gated-at.bofh.it>
2006-08-04 20:51                     ` [RFC][PATCH] A generic boolean Bodo Eggert

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