select、poll、epoll

https://www.cnblogs.com/hsmwlyl/p/10652503.html

sleect监听例程

https://www.jianshu.com/p/a293869bbdb8

https://blog.csdn.net/sinat_36184075/article/details/77170996

https://blog.csdn.net/ygl840455828ygl/article/details/52438111