condition-variable

问题 I was looking through 'Atomic operations library' and came across a new c++20 feature of atomic 'wait' and 'notify_ ' methods. I am curious on what the differences are in regards to std::condition_variable's 'wait' and 'notify_ ' methods. 回答1: std:atomic wait , notify_all and notify_one methods are similar to methods of conditional variables. They allow the implementation of the logic that previously required conditional variable by using much more efficient and lightweight atomic variables.

问题 I was looking through 'Atomic operations library' and came across a new c++20 feature of atomic 'wait' and 'notify_ ' methods. I am curious on what the differences are in regards to std::condition_variable's 'wait' and 'notify_ ' methods. 回答1: std:atomic wait , notify_all and notify_one methods are similar to methods of conditional variables. They allow the implementation of the logic that previously required conditional variable by using much more efficient and lightweight atomic variables.

问题 My question refers specifically to why it was designed that way, due to the unnecessary performance implication. When thread T1 has this code: cv.acquire() cv.wait() cv.release() and thread T2 has this code: cv.acquire() cv.notify() # requires that lock be held cv.release() what happens is that T1 waits and releases the lock, then T2 acquires it, notifies cv which wakes up T1. Now, there is a race-condition between T2's release and T1's reacquiring after returning from wait() . If T1 tries to

问题 My question refers specifically to why it was designed that way, due to the unnecessary performance implication. When thread T1 has this code: cv.acquire() cv.wait() cv.release() and thread T2 has this code: cv.acquire() cv.notify() # requires that lock be held cv.release() what happens is that T1 waits and releases the lock, then T2 acquires it, notifies cv which wakes up T1. Now, there is a race-condition between T2's release and T1's reacquiring after returning from wait() . If T1 tries to

来源： https://stackoverflow.com/questions/64258821/use-of-promise-and-future-to-provide-continous-periodic-notifications-from-one-t

来源： https://stackoverflow.com/questions/64258821/use-of-promise-and-future-to-provide-continous-periodic-notifications-from-one-t

来源： https://stackoverflow.com/questions/56384817/why-wait-with-predicate-solves-the-lost-wakeup-for-condition-variable

来源： https://stackoverflow.com/questions/56384817/why-wait-with-predicate-solves-the-lost-wakeup-for-condition-variable

来源： https://stackoverflow.com/questions/37180547/stdcondition-variable-why-does-it-need-a-stdmutex

来源： https://stackoverflow.com/questions/37180547/stdcondition-variable-why-does-it-need-a-stdmutex