Help with bit-field semantics in C and C++

[Gabriel Dos Reis]

Mike Stump <mrs@apple.com> writes:

[...]

| which if you squint, you can see it more closely matches my example...
| 
| > | e = 7;
| 
| Ok, I blew that one...  I was thinking of a slightly different test
| case.  One that made full use of the full range of the underlying type
| in a portable program.

As repeatedly demonstrated, only use of the bit-sized full range is
covered. Not the whole underlying integer type.

| T<sizeof (e)> x = 7;
| memcpy ((char *)&e, (char *)&x, sizeof (e));
| 
| The issue remains the same...  Could be good DR material...
| 
| > Values of type bool are either true or false.42)
| 
| Yeah, and I was thinking of:
| 
|    42) Using a bool value in ways described by this  International  Stan-
|    dard as ``undefined,'' such as by examining the value of an uninitial-
|    ized automatic variable, might cause it to behave  as  if  is  neither
|    true nor false.

That is a (non-normative) note to remind that a trap representation is
still permitted for bools, not a note that would contractid the very
rule (of which this footnote is appended) that  any value of bool type
is either false or true.