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From: Andy Whitcroft <apw@shadowen.org>
To: hanwen@xs4all.nl
Cc: git@vger.kernel.org
Subject: Re: weird strncmp usage?
Date: Thu, 02 Nov 2006 01:44:36 +0000	[thread overview]
Message-ID: <45494D84.2060402@shadowen.org> (raw)
In-Reply-To: <eibhga$tpg$1@sea.gmane.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

  reply	other threads:[~2006-11-02  1:45 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-11-02  1:26 weird strncmp usage? Han-Wen Nienhuys
2006-11-02  1:44 ` Andy Whitcroft [this message]
2006-11-02  6:51   ` Jeff King
2006-11-02  9:15     ` Johannes Schindelin
2006-11-02  9:59       ` Han-Wen Nienhuys
2006-11-02 11:04   ` Petr Baudis
2006-11-03 21:05   ` Florian Weimer

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