On Mon, 14 Mar 2022 at 14:15, Patrick Palka wrote:
> I think __floating_from_chars_hex should work fine on 16 bit targets,
> so I suppose we could use it in the !USE_LIB_FAST_FLOAT branch as well.

Good point, and even for SIZE_WIDTH >= 32, it might be faster to use
your __floating_from_chars_hex function than to change locale twice
and allocate memory and call strto{f,d,ld}. It certainly avoids the
non-standard errc::out_of_memory result.

So maybe something like the attached semi-tested patch.