Taking a test for a job

[Dave Thompson]

The representation for (nonnegative) signed values must be valid for
unsigned as well, but a quick search doesn't give me a guarantee for
the reverse.

When passed as an unprototyped (6.5.2.2p6) or variadic (7.15.1p2)
argument, an unsigned integer with a value in range of the
corresponding (= same rank) signed type must work, as well as the
reverse (where any nonnegative value is in range). These aren't stated
as requirements on representation, but there doesn't seem to be any
other practical or even workable way to implement them.

- David.Thompson1 at worldnet.att.net