基本概念、基本函数：
https://www.cnblogs.com/xuejiale/p/10817045.html
pthread_cancel 相关处理过程：
https://blog.csdn.net/sty124578/article/details/79460837
线程资源的释放问题：
https://blog.csdn.net/github_27263697/article/details/78934061