Floating Point, how much can I trust less than / greater than comparisons?

Question

Let\'s say I have two floating point numbers, and I want to compare them. If one is greater than the other, the program should take one fork. If the opposite is true, it should

Answer 1

Short answer, it is guaranteed never to be called.

If a then a will always be less than b plus a positive amount, however small. In which case, testing if a is less than b + an amount will be true.

The third case won't get reached.