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Date:      Tue, 3 Oct 2000 14:49:11 -0500
From:      Dan Nelson <dnelson@emsphone.com>
To:        Larry Lile <lile@stdio.com>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: Question about -Wchar-subscripts
Message-ID:  <20001003144911.A12803@dan.emsphone.com>
In-Reply-To: <Pine.BSF.4.05.10010031536460.75472-100000@heathers.stdio.com>; from "Larry Lile" on Tue Oct  3 15:46:36 GMT 2000
References:  <Pine.BSF.4.05.10010031536460.75472-100000@heathers.stdio.com>

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In the last episode (Oct 03), Larry Lile said:
> 
>     ...we get scores of warnings about using characters as subscripts
>     to an array (-Wchar-subscripts), which generates so much noise as
>     to mask real warnings burried within. Therefore, I would like to
>     suppress this warning unless someone can explain why using a char
>     as an array subscript is in any way an illegitimate thing to do.
>     As far as I can tell, getting rid of the warning by changing the
>     code would require adding a large number of frivolous casts to
>     scores of source files...
> 
> So why is using a "char" as an array subscript wrong?  I had always
> avoided it because the compiler complained and that was good enough
> for me.

Because your char value could be negative and end up referencing memory
before your array start.  Mainly a problem with the ctype macros and
high-ascii characters.

-- 
	Dan Nelson
	dnelson@emsphone.com


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