These functions allow users to test conformance to -ieee754. Their use is not otherwise recommended.
logb x and logbf x return x s exponent n, a signed integer converted to double-precision floating-point. logb ±oo = +oo; logb 0 = -oo with a division by zero exception.
scalb x n and scalbf x n return x *(2** n) computed by exponent manipulation. If n is not an integer, ±oo, or an NaN, the result is unspecified.
significand x and significandf x return sig, where x := sig * 2** n with 1 <= sig < 2. significand x and significandf x are not defined when x is 0, ±oo, or NaN.