Negative NaN is not a NaN?

Question

While writing some test cases, and some of the tests check for the result of a NaN.

I tried using std::isnan but the assert failes:

Asse         


        

Answer 1

There's C99 isnan() which you should be able to use.

If in your implementation it does not work correctly (which one is that?) you can implement your own, by reinterpret_casting to long and doing IEEE bit magic.