Marc Nieper-Wißkirchen wrote: > I could reformulate my question to: "Is there a way to produce a (quiet) > NaN that won't occur as a result of the C library functions?"
There are 2^51 possible quiet NaNs [1]. I would guess that the hardware and libc functions produce only a small portion of this space (because what would be the point of encoding additional information in the result of 0.0 / 0.0, sqrt(-31.2), acos(-1.4), etc.?). But I don't really know. You would need to find out yourself. Bruno [2] https://en.wikipedia.org/wiki/Double-precision_floating-point_format