编辑“︁GameDesign”︁（章节）

==Synchronization between Game and RP Managers==
Why bother with this? Well, imagine that a player logs out while the perception is being built, it will no longer be accessible by the RP Manager when it expects the object to be there, or if RPManager tries to remove a player which has already been removed, these situations are very serious as they will probably make the server fail.

So we must synchronize the Game and RP Managers.

The idea behind the solution is that the each manger requests access to the PlayerEntryContainer via a central mutex (a mutex is a syncronisation element attached to a resource, which can be owned by one task at any point in time. If the mutex is owned already when a task tries to access the object protected by it then the mutex will inform the task that it doesn't have access at this point in time to the object).

There are two types of accesses, read accesses and write accesses. Note that two readers can access an object in parallel but only one write can happen at the same time.
In GameManager there are only Write actions, as this manager only modifies the state of the PlayerContainer. However, in the RP manager we have both Reads, when we build the perceptions, and Writes when the manager removes idle players. Hence here we have two different locks.

[[Marauroa]]