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Synchronizing Processes

Several interprocess synchronization primitives are available, including mutexes and semaphores. All types follow similar patterns for sharing themselves across processes, either by being allocated in a shared memory space or being shared via name.

The named variants of these classes take a String name for the object. If no object of that name exists, it is created. If any process has already created that type of object with the same name, then it will open the existing object. Two processes which use an object of the same name will synchronize with each other. If the Adopt tag instance is passed to the constructor then the construction will fail if an object of that name does not exist, i.e. it will not be created if not already present.

The unnamed variants of these primitives are not managed by name by the operating system. Instead they are constructed in place normally. To be shared with another process, the memory where they are constructed should be shared, e.g. via the SharedMemory class.

注意

Interprocess synchronization primitives can be significantly more expensive than purely intraprocess ones, so these types should not be used when only synchronizing threads in a single process.

Shared Monitors​

The SharedMonitor and SharedNamedMonitor types provide a monitor that is useful across processes. This type is similar to the Monitor type used within a process.

Shared Mutexes​

There are four interprocess mutex types available:

  • SharedMutex
  • SharedPriorityInheritingMutex
  • SharedNamedMutex
  • SharedNamedPriorityInheritingMutex

Each of these mutexes acts similar to the intraprocess mutexes. All interprocess mutexes have deadlock detection as long as the underlying platform supports it.

Shared Semaphores​

Two interprocess semaphores are available, the SharedSemaphore and SharedNamedSemaphore. These behave identically to the intraprocess semaphore, except for being usable across processes.

Shared Latches​

Two interprocess latches are available, the SharedLatch and SharedNamedLatch. These behave identically to an intraprocess latch.