[RFC] do_get of floats vs underflow

[Benjamin Kosnik]

> Since, according to the standard, the behavior of num_get is "as-if"
> scanf, not "as-if" strtof, and scanf certainly doesn't fail in any sense
> in case of floating point underflow (at least this is what I'm seeing on
> linux), I would guess we could just avoid checking whether errno ==
> ERANGE, don't fiddle at all with errno, and instead just check that the
> value returned by strtof is != HUGE_VAL && != -HUGE_VAL.

Indeed.

> Or dot we have reasons to believe people are relying (uncorrectly) on
> failbit being set in case of underflow? When evaluating this issue, we 
> should also consider that, according to C99, 7.20.1.3/10, about strtof & 
> co, in case of underflow "whether errno acquires the value ERANGE is is 
> implementation-defined". Thus, I would say I do not consider the latter 
> expectation very reasonable, in general.

Yes, I think your analysis is sound. Your follow-up patch looks good to me.

best,
benjamin