Would service socket be closed before core dump or after it?

Question

If a service is crashed and generate a core dump, will the socket which the service listens be closed immediately or closed when the core dump is done.

Answer 1

What I see in my application is that a listening socket is not closed when a signal arrives and Linux starts writing a core file. It is only closed when the core file has been written.

In order to change this behavior it is possible to close a listening socket right in a signal handler. close() is async-signal-safe: http://pubs.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html