Re: return'ing a struct and trap representations

[Paul Eggert]

>> Should be: for integer and pointer types there are _no_ "trap 
>> representations".
>
> I don't think that is guaranteed by C99.

That's correct.  As I recall, only unsigned char objects are
guaranteed to be free of trap representations.

> Certainly the practical value of this for gnulib is questionable.

I've heard that some C implementations do support trap representations
of pointers in hardware, and that some debugging C implementations
also have trap representations for integers.  See, for example
<http://www-128.ibm.com/developerworks/power/library/pa-ctypes3/>.

I've never knowingly used such implementations, thought I wouldn't be
surprised if I used one without knowing it.