说明：  提供了一种简单的单向“进程间通信”（interprocess communication, I P C）机制。这个机制的名字非常古怪，叫作“邮槽”（M a i l s l o t）。用最简单的话来说，通过 邮槽，客户机进程可将消息传送或广播给一个或多个服务器进程。
(provides a simple one-way "communication process" (interprocess commun ication, I P C) mechanisms. The name of this mechanism is very strange, called "Post Groove" (M.'s a i l l o t). With the most simple words, by mail chutes, and the client process can be transmitted or broadcast news to one or more server processes.)