套接字编程，C中有多个客户端的服务器

I am running into some problem with my server. I am trying to reading inputs from multiple clients but I can only do it one at a time. I think my server's code does not have an issue. So I assume that my local clients are the ones that are actually at fault here. Are each clients exactly the same as the other if I want to handle multiple clients with different sockets. or are they different in some ways?I am running into some problem with my server.