_PyLong_Frexp returns a double x and an exponent e such that the
true value is approximately equal to x * 2**e. e is >= 0. x is
0.0 if and only if the input is 0 (in which case, e and x are both
zeroes); otherwise, 0.5 <= abs(x) < 1.0. On overflow, which is
possible if the number of bits doesn't fit into a Py_ssize_t, sets
Availability: >= 2.7
OverflowError and returns -1.0 for x, 0 for e.
_PyLong_Frexp returns a double x and an exponent e such that the true value is approximately equal to x * 2**e. e is >= 0. x is 0.0 if and only if the input is 0 (in which case, e and x are both zeroes); otherwise, 0.5 <= abs(x) < 1.0. On overflow, which is possible if the number of bits doesn't fit into a Py_ssize_t, sets Availability: >= 2.7 OverflowError and returns -1.0 for x, 0 for e.