Question

我要问你,如果我选择的话,哪一个一致设施(CMutex, CSemaphore, CEvent)能够使C++/MFC成为多管齐下。

这是一个真正的时间,即机器设想的应用,现在需要同时执行,而且需要从以前单一阅读的状况中重新加以证明。

A single iteration of my workflow is the following. I have 2 producers A,B (MFC Workers) that need to fill two separate data structures (1 each). A third thread, a consumer (MFC Worker as well) is blocked, until both data become available from A and B. Then, producers A and B must block (each, upon their data completion), C must wake up, perform a calculation, unblock A and B to continue and become blocked again, waiting for the next segments.

I must not use queues (Actor-like) - the blocking is a requirement :(
I tried CEvent and it works. AutoResetEvents for A,B to unblock a CMultiLock call on C and then a ManualResetEvent->Set() from C, to unblock A and B waiting on the latter event. My concern is when to reset this event (in case e.g. A miss the whole Set and then Reset.)
Do semaphores with plurality of 2 may stand for a better solution?

最好。

Answer 1

C必须等两件事情才能发生,因此最符合逻辑的是,它要等两件自动打造的物体:一个是A设定的,另一个是B。

When C is done, A and B must each then wait for a notification. Since there are two threads, and both must wake up, the natural thing is to use another pair of auto-reset CEvent objects, one for each of A and B. C can then set both when it is done.

一张2张 count光的ema光灯将用来唤醒C-C,两度等待,而A和B每一方都通知——但这意味着C在第一次通知之后必须警醒,以等待第二次,这并不理想。

之后,用2个 count子来检测A和B,就有可能发生偷窃的催泪和混乱。 C 信号是ema的两倍。催复和发出信号,处理和通知C,然后再等待ema。自2006年以来 Bn t 尚未消亡,仍然有烟雾,因此A再次照亮。同时 B并不 st,因为它获得了另一个信号,C被 st,因为它将等待B的下一个价值。

另一种选择是使用Windows vant Variable AP,而不是使用事件,但在这方面似乎只有MFC包裹。见。

Answer 2

我将略微修改你的备选办法2——利用CMultiLock进行两次活动,以阻止C;然后使用另一场<>pair<>>>>事件,以阻止A和B.C。然后,你不再有争.。

Answer 3

我建议采用一种信号处理系统,使用一种受相互保护的反射系统。这使得所有同步工作都局限于一个不另.的小类别。

A starts
A writes A-Data
A signals
A stops

B starts
B writes B-Data
B signals 
B stops

C starts
C reads A-Data and B-Data
C starts A, B
C stops


*Signal Class*

Mutex protected counter attribute

Receives signal for A, increment counter
Receives signal for B, increment counter
IF counter equals 2,  clear counter and start C

Answer 4

你只能使用CEvent物体和WaitForMultipleObjects,允许你通过第三个参数(WaitAll)等待这两个物体。

http://msdn.microsoft.com/en-us/library/windows/desktop/ms687025%28v=vs.85%29.aspx

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