Is mixing char and int types as parameters portable?

[Guido van Rossum]

I'd like to hear the opinion of the net on the following (MAIL please;
I'll summarize):

The K&R book says that chars are widened to ints before anything is
done to them (except when used as lvalue, I think).  Does this mean
that the following code is portable, even to the weirdest machines?

	foo(c) char c; { ... }

	bar(i) int i; { ... }

	main() { foo(100); bar(' '); }

(Please, no guesses -- I can GUESS it's right myself.)

	Guido van Rossum, CWI, Amsterdam     guido at mcvax