How do you interrupt a socket.ReceiveFrom call?

Question

I have a udp client that is listening for multicast messages. When it gets a message the message is parsed and the client resumes listening. If the application is shutdown while the socket.ReceiveFrom method is blocking, how can I interrupt this process and continue?

I have the socket running on a different thread and I've tried to issue an interrupt to that thread and then join, but the interrupt doesn't work the socket.ReceiveFrom never returns unless it gets a message.

I have also tried setting a timeout on the socket, but this isn't ideal since it generates an exception on timeout and since I'm always listening I will be generating a ton of timeouts, catching them and then go back to listening.

Any ideas what i can try here?

Answer 1

Found I can make the socket available outside the thread being blocked and can call a socket.Close. This interrupts and throws a SocketException. Still seems a bit dirty but it gets the job done.

Anyone have a better way?

Answer 2

I am not socket expert, but can still try.

Use combination of following two things to make a non-blocking socket.

1) Use select function with timeout to wait on a particular socket. After timeout check if you still want to wait on that socket or not.

2) Make you recvfrom call non-blocking by using O_NONBLOCK. http://www.kegel.com/dkftpbench/nonblocking.html

Use the above link to study about how to make recvfrom non-blocking.

Google for select.