Character types in ANSI C

[drw at cullvax.UUCP]

drw at cullvax.UUCP (Dale Worley) writes:
> Well, the char's are all widened into the 'appropriate' int types.
> (These are called integral promotions, or some such.)  Then the
> appropriate comparisons of int's and/or unsigned int's are performed.
> 
> I think that the rule for widening char's to int's is "a character
> type is promoted to unsigned int if all possible values of the
> character type can be represented by unsigned int, otherwise it is
> promoted to int".

Wrong!  The rule is "char is promoted to int if all possible values of
the char type can be represented by int, otherwise it's unsigned int".
(Personally I can't imagine when a (signed or unsigned) char couldn't
be represented as int.)

> Thus, you get:
> 	p2 = p2		<->	(unsigned int)p2 = (unsigned int)p2
> 	p3 = p3		<->	(int)p3 = (int)p3
> 	p2 = p3		<->	(unsigned int)p2 = (unsigned int)(int)p3
> (p1 acts like p2 or p3, depending on whether chars are signed)

Wrong!  All of these get casted directly to int and compared.

Dale
-- 
Dale Worley		Cullinet Software
UUCP: ...!seismo!harvard!mit-eddie!cullvax!drw
ARPA: cullvax!drw at eddie.mit.edu