This would make the epcho value increase smoothly even after 2038 (but not forever).
The logic behind the convertion: time() returns (- 2** 31) for 2038-01-18-20:14:07, which should be 2 * 31; returns (-2**31 + 1) for 2038-01-18-20:14:08, which should be (2 ** 31 + 1) and ... so the difference between what returned from time() and what it should be is always 2 ** 32.