Re: toupper and warnings

[tlaronde%polynum.com@localhost]

On Thu, May 06, 2021 at 12:52:36PM -0700, Greg A. Woods wrote:
>[...] 
> Well I don't actually do that.
> 
> Which is to say my implementation's goal is to turn them into properly
> promoted values and access the flags array in such a way that this does
> not and cannot "cause" UB.  My implementation carefully tests for a -1
> and then if it is not -1 it uses a cast and assignment to an unsigned
> char, the value of which is then used to access the array.  I.e. totally
> safe _and_ UB-free.
> 

I guess you mean testing not against -1 but testing against EOF? Because
strictly speaking, EOF could be whatever integer value not in the
unsigned char range (and this is why too casting to unsigned char is
necessary because -1 is in the range of a signed char; after all, not
considering EOF for other usages, in this case EOF could be an
impossible signed or unsigned char value).
-- 
        Thierry Laronde <tlaronde +AT+ polynum +dot+ com>
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