If you use kqueue(), should you set O_NONBLOCK on your file descriptors? In other words, does kqueue() guarantee that the next I/O operation on a ready file descriptor will not block, regardless of whether O_NONBLOCK is set?
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问题:
回答1:
If you use kqueue(), should you set O_NONBLOCK on your file descriptors?
Nope.
In other words, does kqueue() guarantee that the next I/O operation on a ready file descriptor will not block, regardless of whether O_NONBLOCK is set?
Yep.
回答2:
You do not need to. However, I generally do as a sanity check. This makes operations like read() return -1 and set errno to EWOULDBLOCK. I would much rather get an EWOULDBLOCK and know that my implementation of kqueue is buggy than have read() calls block (and therefore my program freeze) for unknown reasons.