http://blog.csdn.net/bullbat/article/details/7097213
http://os.chinaunix.net/a2009/0503/992/000000992793.shtml
http://blog.csdn.net/mishifangxiangdefeng/article/details/7595023
（四）中断和异常
原文：http://www.cnblogs.com/liuchengchuxiao/p/4207380.html
