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From: Andy Whitcroft <apw@shadowen.org>
Subject: Re: weird strncmp usage?
Date: Thu, 02 Nov 2006 01:44:36 +0000
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To: hanwen@xs4all.nl
Sender: git-owner@vger.kernel.org

Han-Wen Nienhuys wrote:
> 
> Hi,
> 
> the git source seems full of calls similar to
> 
>   strncmp (x, "constant string", 15)
> 
> is there a reason not to use something like
> 
>   int
>   strxmp (char const *x, char const *y)
>   {
>     return strncmp (x, y, strlen (y));
>   }
> 
> everywhere?

If you are doing these a _lot_ then there is a significant additional
cost to using strlen on a constant string.

That said if you know its constant you can also use sizeof("foo") and
that is done at compile time.  Something like:

#define strxcmp(x, y)	strncmp((x), (y), sizeof((y))

-apw