位运算的请教继续 #81
Answered
by
Codesire-Deng
KleinSteven
asked this question in
Q&A
位运算的请教继续
#81
-
|
抱歉，由于我这边的问题，无法在源discussion回复，所以新开一个讨论 |
Beta Was this translation helpful? Give feedback.
Answered by
Codesire-Deng
Sep 28, 2023
Replies: 1 comment 1 reply
-
|
原理是在 64 位机器上，io_info 内含一个指针，所以至少是按 8 字节对齐的，其地址的低 3 位总是 0。 |
Beta Was this translation helpful? Give feedback.
1 reply
-
|
好的，感谢解答 |
Beta Was this translation helpful? Give feedback.
Answer selected by
KleinSteven
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
io_info.as_user_data()的低 3 位保证为 0，这是由 static_assert 确保的，进而后面的位运算可以成立。原理是在 64 位机器上，io_info 内含一个指针，所以至少是按 8 字节对齐的，其地址的低 3 位总是 0。