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SubjectRe: [IDEA+RFC] Possible solution for min()/max() war

On Thu, 30 Aug 2001, Daniel Phillips wrote:
>
> Yes, in the signed/unsigned case the comparison generated is always
> unsigned.

Well... No.

If you compare a signed integer with a unsigned char, the char gets
promoted to a _signed_ integer, and the comparison is signed. It is NOT
a unsigned comparison.

And THIS is one example of why it gets complicated.

The C logic for type expansion is just a tad too easy to get wrong, and
the strict type-checking you normally have with well-written ANSI C simply
does not exist for integer types. The compiler will silently just do the
promotion..

Somebody mentioned -Wsign-compare. Try it with the example above. It won't
warn at all, exactly because under C both sides of such a compare have the
_same_ sign, even if one is a "unsigned char", and the other is a "signed
int".

Try it yourself if you don't believe me.

Please guys. The issue of sign in comparisons are a LOT more complicated
than most of you seem to think.

Linus

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