How to interpret this semaphore?
What does the lock function here specifically mean? ?
Why is sembuf.sem_op -1 instead of 1 when unlocking? ?
What does the lock function here specifically mean? ?
Why is sembuf.sem_op -1 instead of 1 when unlocking? ?
大家讲道理2017-06-07 09:26:21
It is recommended that you do it yourself, check more, and don’t be a hand-in-hand party.
sembuf.sem_op does not have to be -1 or 1, only positive and negative, indicating different operations. 
