pcap_get_selectable_fd(3pcap) on macOS
The text 70bb4fd81a38, as Mac OS X 10.6.8, Mac OS X 10.6.7, Mac OS X 10.6.6, Mac OS X 10.6.5, Mac OS X 10.6.4, Mac OS X 10.6.3, Mac OS X 10.6.2, Mac OS X 10.6.1, Mac OS X 10.6 shipped it.
get a file descriptor on which a select() can be done for a live capture