https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81122
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Heinz Kohl from comment #8) > o.k., it looks like a flawy definition. Yes, that's why it's being fixed by the standards committee. I don't want to change our implementation yet, until the intention of the committee is clear. > First of all, it would be nice, if you would refer my error message to the > right instance. I don't know what this means. We know you can't currently read hex floats using istreams with libstdc++, we know it's a defect in the standard, we're working on it.