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From: "Måns Rullgård" <mans@mansr.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] Introduce a global bool type
Date: Tue, 22 Jan 2013 12:59:11 +0000	[thread overview]
Message-ID: <yw1xham9e5ls.fsf@unicorn.mansr.com> (raw)
In-Reply-To: <20130122084103.5d37ff6b@lilith> (Albert ARIBAUD's message of "Tue, 22 Jan 2013 08:41:03 +0100")

Albert ARIBAUD <albert.u.boot@aribaud.net> writes:

> Hi M?ns,
>
>> In other words, boolifying on use rather than on assignment is generally
>> safer and usually at least as efficient.
>
> Except when assigning a C = A & B where A and B happen to have
> no common bit set. Which is why I think 'boolifying' as soon as
> possible -- on assignment -- is way safer than on use.

But that's not a boolean context.  You should use A && B.

The thing is, when using a value, you know if you need a boolean, but
not necessarily (easily) how the value was assigned.  Conversely, when
assigning a value, you do not know how it will be used.  By always
boolifying on use, you remove the need to keep track of which values are
"true" booleans and which ones are arbitrary values (or even pointers)
you happen to be using in a boolean fashion.

-- 
M?ns Rullg?rd
mans at mansr.com

  reply	other threads:[~2013-01-22 12:59 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-07 22:10 [U-Boot] [PATCH] Introduce a global bool type York Sun
2013-01-07 22:29 ` Scott Wood
2013-01-07 22:32 ` [U-Boot] [u-boot-release] " Timur Tabi
2013-01-07 22:39 ` [U-Boot] " Wolfgang Denk
2013-01-07 22:50   ` Scott Wood
2013-01-07 22:54   ` Måns Rullgård
2013-01-08  6:25     ` Wolfgang Denk
2013-01-08 16:51   ` Tabi Timur-B04825
2013-01-08 17:49     ` Wolfgang Denk
2013-01-08 17:53       ` Timur Tabi
2013-01-08 19:07         ` Wolfgang Denk
2013-01-08 19:09           ` Timur Tabi
2013-01-08 19:56           ` York Sun
2013-01-08 21:39             ` Wolfgang Denk
2013-01-08 21:43               ` York Sun
2013-01-08 21:46                 ` Scott Wood
2013-01-19  9:30           ` Albert ARIBAUD
2013-01-21 18:05             ` Scott Wood
2013-01-21 22:36               ` Måns Rullgård
2013-01-21 22:51                 ` Scott Wood
2013-01-21 23:08                   ` Måns Rullgård
2013-01-22  7:41                     ` Albert ARIBAUD
2013-01-22 12:59                       ` Måns Rullgård [this message]
2013-01-08 18:34       ` Bernhard Walle
2013-01-08 19:08         ` Wolfgang Denk

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