Interprocess message queue

摘要

The interprocess message queue operates in a multiprocessing environment to ensure that interprocess messages sent from an originating task do not overflow the destination task resource pipe. To prevent message overflow, the destination task creates a message queue when a communication session is originated and populates this message queue with n message reserved for the originating task. Each time the originating task wishes to send a message to the destination task, the originating task first retrieves one of the reserved messages from the destination task message queue. Once the message is retrieved from the message queue, the originating task is assured that memory space is available in the resource pipe to send a message. When the destination task receives the message, the destination task reads the message and flags the message as old, thereby allowing another message to be sent, since the originating task can now remove this old message from the message queue to make room for a new message. In this way, the destination task resource pipe never overflows.