sigaction
引自：https://blog.csdn.net/qq_20853741/article/details/113547906
SIGPIPE
https://www.cnblogs.com/lit10050528/p/5116566.html
sem_init
引自：https://blog.csdn.net/qq_33527943/article/details/80457903
pthread_create
socketpair
转自：https://blog.csdn.net/wufuhuai/article/details/79747912
EAGAIN
转自：https://www.cnblogs.com/big-xuyue/p/3905597.html