Re: weird strncmp usage?

From: Andy Whitcroft <apw@shadowen.org>
Date: Nov 2, 2006, 01:44 UTC
Message-ID: <45494D84.2060402@shadowen.org>
In-Reply-To: <eibhga$tpg$1@sea.gmane.org>

Han-Wen Nienhuys wrote:

Show 16 quoted lines

> 
> 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