datetime - os.difftime(t2, t1) 的用途是什么，但 t2 - t1 未涵盖？

Question

在此代码中

t1 = os.time()
do_something_slow()
t2 = os.time()

elapsed_diff = os.difftime(t2, t1)
elapsed_sub  = t2 - t1

什么情况下elapsed_diff会与elapsed_sub不同？

Answer 1

在非Posix系统中，不能保证os.time返回的值可以直接相减。

In the GNU C Library, you can simply subtract time_t values. But on other systems, the time_t data type might use some other encoding where subtraction doesn't work directly. [1]