Getting file descriptor associated with a port

Hi,

Is there a way to retrieve (using c) the port associated with a certain
file
descriptor?

Say I have a file descriptor returned from socket, which has been sent
to a call to bind(). At some stage, I want to retrieve the port number
associated with the socket. How is that done? I tried looking up the
ioctl_list, but couldn't really make heads ot tails of it...

For what I need, retrieving the file descriptor associated with a port
is also fine.

Thanks

Wait...found it - getsockname, of course. Silly me.