title: Socket Select with empty fd set
body: <p>Suppose you have an fd set which can have zero or more sockets in it. When I try to call select operation on empty fd set, what I get is -1 as the number of fds which are set, meaning error. So what would you suggest to overcome this problem, you might say do not call if empty but I have a loop and any time fd set can hold 0 or more sockets. What is the best approach about this problem? (we are on C programming language)</p>