std::ios_base::iword. Then one could safely modify the flags, and one could define manipulators that do so. However, for that to work with dynamically linked libraries, a
.cppfile would have to be added to the library. It was judged be more desirable to have a headers only library, than to have mutable flags and manipulators.
nonfinite_num_putthrows an exception when the
trap_nanflag is set and an attempt is made to format infinity or NaN. It would be better if the facet set the fail bit of the stream. However, facets derived from
std::num_putdo not have access to the stream state.