Non-blocking client and server sockets in C [closed]

Answer 1

I think you're asking how to perform I/O on a non-blocking socket. Beej's guide has been around for a long time; it covers all this and more, with good code samples.

Answer 2

The idea with non-blocking I/O is to be able to handle multiple sockets without resorting to multiple threads. The central part here is I/O de-multiplexing, i.e. a call to select(2) or poll(2) (or platform specific functions like epoll(7) or kqueue(2)).

Here's a brief introduction.