Date: Thu, 7 Mar 2002 15:27:49 -0500 From: Garance A Drosihn <drosih@rpi.edu> To: "Brian T.Schellenberger" <bts@babbleon.org> Cc: hackers@FreeBSD.ORG Subject: Re: RFC: style(9) isn't explicit about booleans for testing -- an actual analysis of the code! Message-ID: <p05101508b8ad7b67c653@[128.113.24.47]> In-Reply-To: <20020307071630.E26DBBA03@i8k.babbleon.org> References: <52204.1015480748@critter.freebsd.dk> <20020307071630.E26DBBA03@i8k.babbleon.org>
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At 2:16 AM -0500 3/7/02, Brian T.Schellenberger wrote:
>Maybe your brain has gotten used to it, but to us ordinary
>mortals, even us ordinary mortals who've been slogging C
>code for time periods that can be measured in decades
>(yikes!), it is very tempting to read
>
> if (!strcmp(a,b,l))
>
>as "if the strings don't compare" which, in ordinary usage,
>means don't compare *equal*. But of course the C program
>is going to proceed to do exactly the opposite of that.
Okay, I will agree I have made that mistake a few times. Not
often, but it really burns me up when I realize that's the
source of some bug. So, that sounds like a good reason.
>But *ALL* of this is beside the nominal point ANYWAY, which
>is to discuss the proper wording for the man(9) style guide
>which is supposed to document how things things are actually
>done in the kernel, not personal preference.
As to the wording, PHK suggested that the wording for this
rule in style(9) be changed:
- - -
get rid of the word boolean, ie: change
Do not use ! for tests unless it is a boolean, e.g. use
to
Do not use ! for tests unless it is an integer type, e.g. use
- - -
Dave O'Brien claimed the very same rule was *only* there to
prevent "if (!strcmp(a,b))".
May I suggest that we probably want two different rules? Change
the current rule so it says 'integer type' instead of 'boolean'
(which doesn't really exist in C anyway), and then add the rule
about strcmp()?
--
Garance Alistair Drosehn = gad@eclipse.acs.rpi.edu
Senior Systems Programmer or gad@freebsd.org
Rensselaer Polytechnic Institute or drosih@rpi.edu
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