linux-kernel - Re: [PATCH 12/19] staging: lustre: libcfs: remove == 0 testing

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Date:   Fri, 18 Nov 2016 14:01:27 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     James Simmons <jsimmons@...radead.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        devel@...verdev.osuosl.org,
        Andreas Dilger <andreas.dilger@...el.com>,
        Oleg Drokin <oleg.drokin@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Lustre Development List <lustre-devel@...ts.lustre.org>
Subject: Re: [PATCH 12/19] staging: lustre: libcfs: remove == 0 testing

On Thu, Nov 17, 2016 at 02:35:50PM -0500, James Simmons wrote:
> Testing == 0 is not kernel style so remove this
> type of testing from libcfs.
> 

That's not true.  Checkpatch.pl won't complain.

Not everyone has thought about it or agrees with me but there are time
when == 0 is idiomatic.  For example, if you are talking about the
*number* zero then it should probably be == 0.  If it's like "rc == 0"
then "rc" doesn't mean the number it means success/fail so it should be
"if (!rc) ".  But it's intuitive to say "if (len == 0) ".

The other place is strcmp() and friends where it's much more intuitive:

	strcmp(a, b) == 0 means a == b
	strcmp(a, b) < 0 means a < b
	strcmp(a, b) != 0 means a != b

regards,
dan carpenter