linux-kernel - Re: [linux-pm] [PATCH] ACPI: replace strlen("string") with sizeof("string") -1

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Date:	Tue, 07 Aug 2012 05:07:06 +0400
From:	Pavel Vasilyev <pavel@...linux.ru>
To:	Alan Stern <stern@...land.harvard.edu>
CC:	Pavel Machek <pavel@....cz>, Len Brown <lenb@...nel.org>,
	linux-acpi@...r.kernel.org, linux-pm@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org, Len Brown <len.brown@...el.com>
Subject: Re: [linux-pm] [PATCH] ACPI: replace strlen("string") with sizeof("string")
 -1

06.08.2012 23:59, Alan Stern пишет:
> On Mon, 6 Aug 2012, Pavel Vasilyev wrote:
>
>>>> http://www.gossamer-threads.com/lists/engine?do=post_attachment;postatt_id=41157;list=linux
>>>
>>> Interestingly, many (all?) of the changes in that patch are wrong
>>> because they don't try to match the terminating '\0'.  As a result,
>>> they will match against extensions of the target string as well as the
>>> target string itself.
>>>
>>
>> strNcmp compare N bytes - http://lxr.linux.no/#linux+v3.5/lib/string.c#L270
>> memcmp compare N bytes  - http://lxr.linux.no/#linux+v3.5/lib/string.c#L651
>
> Yes.  So if s contains "abcde" then
>
> 	memcmp(s, "abc", 3) and strncmp(s, "abc", 3) will both return 0, and
> 	memcmp(s, "abc", 4) and strncmp(s, "abc", 4) will both return 1.

No matter what is contained in *s, "abcde" or "abcxxx",
are important first N bytes. The second example, you see,
a little bit stupid, and devoid of logic. :)


-- 

                                                          Pavel.
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