[Cfp-interest 2026] Re: FLT_HAS_SUBNORM is 0: what is fpclassify(<subnormal>)?

[David Hough CFP]

> I do not know if a negative subnormal would be flushed to -zero or +zero.

Signs were preserved on the systems I knew about.

> This matters for (at least):
  fpclassify()
  iscanonical()
  issubnormal()
  iszero()
  signbit()
  nextafter()
  nexttoward()
  nextup()
  nextdown()

I'd suggest that these kinds of functions ignore the flush mode and 
identify subnormals properly - the actual arithmetic would do whatever it
did in nonstandard mode.