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Date:      Tue, 3 Oct 2000 16:13:14 -0400 (EDT)
From:      Thomas David Rivers <rivers@dignus.com>
To:        dnelson@emsphone.com, lile@stdio.com
Cc:        hackers@FreeBSD.ORG
Subject:   Re: Question about -Wchar-subscripts
Message-ID:  <200010032013.QAA81703@lakes.dignus.com>
In-Reply-To: <20001003144911.A12803@dan.emsphone.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.
> 

 That's an interesting reason... any variable can be negative (well,
 except for the unsigned types...)  - what's so interesting about
 `char'?  Is it simply ctype macros that are the concern, or something
 "bigger"?

	- Dave R. -
 


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