Using multiple sockets, is non-blocking or blocking with select better?
- by JPhi1618
Lets say I have a server program that can accept connections from 10 (or more) different clients. The clients send data at random which is received by the server, but it is certain that at least one client will be sending data every update. The server cannot wait for information to arrive because it has other processing to do. Aside from using asynchronous sockets, I see two options:
Make all sockets non-blocking. In a loop, call recv on each socket and allow it to fail with WSAEWOULDBLOCK if there is no data available and if I happen to get some data, then keep it.
Leave the sockets as blocking. Add all sockets to a fd_set and call select(). If the return value is non-zero (which it will be most of the time), loop through all the sockets to find the appropriate number of readable sockets with FD_ISSET() and only call recv on the readable sockets.
The first option will create a lot more calls to the recv function. The second method is a bigger pain from a programming perspective because of all the FD_SET and FD_ISSET looping.
Which method (or another method) is preferred? Is avoiding the overhead on letting recv fail on a non-blocking socket worth the hassle of calling select()?
I think I understand both methods and I have tried both with success, but I don't know if one way is considered better or optimal. Only knowledgeable replies please!
