说明：  在进行linux服务器编程时经常要用到消息队列编程,但直接使用系统调用可能还不能实现需要.此例子演示了怎样在用内核调用操作消息队列,控制消息队列溢出,消除"死"消息的方法.
(during regular programming to be used when the message queue programming, but the direct use of system calls may also need to achieve. this example demonstrates how to use the core operation called Message Queue, control Message Queue overflow, eliminating the "death" of news.)