C语言 socket资料
recv带有标志MSG_DONTWAIT | TCP套接字上的MSG_PEEK
http://cn.voidcc.com/question/p-perefbfz-pn.html
Linux C语言的Socket编程例子(TCP和UDP)
https://blog.csdn.net/u011426247/article/details/80572623
linux c语言 fcntl函数说明
https://blog.csdn.net/lihuibo128/article/details/43667755
recv函数
https://www.cnblogs.com/sky-of-chuanqingchen/p/4123383.html