Socket listen doesn't unbind in C++ under linux

Question

I have a socket that listens on some port. I send the SIGSTOP signal to the thread that waits on the port (using accept) and terminate it. then I close the fd of the socket

Answer 1

I think the problem is that you have not properly closed the socket and/or your program.The socket probably still exists in the OS. check it with something like nestat -an. You should also check if your process has exited. If it has correctly ended, it should have closed your socket.

What you should do is :

• interrupt your thread with a signal.
• when interrupted your thread should cleanly close the socket before the end.
• then you can cleanly exit from your program.

my2cents,

Answer 2

Did you know that sockets are typically kept in a kind of limbo for a minute or two after you've finished listening on them to prevent communications intended for the previous process coming to yours? It's called the 'TIME_WAIT' state.

If you want to override that behaviour use setsockopt to set the SO_REUSEADDR flag against the socket before listening on it.

Answer 3

See: Using SO_REUSEADDR - What happens to previously open socket?