read keyboad input while displaying data on terminal

I am working on a socket programming assignment, i have to join a multicast group and get data from that group, while recieving data if i need to leave the group i just want the user to enter quit on the terminal, and i want to terminate the recieving of messages. I tried the readline() function but it seems to be a blocking call, is there a non-blocking read ???? would like to know your ideas.

Thanks.