pcap_get_selectable_fd(3) on FreeBSD
The text b8a848d707a0, as FreeBSD 13.4-RELEASE, FreeBSD 13.3-RELEASE, FreeBSD 13.2-RELEASE, FreeBSD 13.1-RELEASE, FreeBSD 13.0-RELEASE, FreeBSD 12.4-RELEASE, FreeBSD 12.3-RELEASE, FreeBSD 12.2-RELEASE, FreeBSD 11.4-RELEASE shipped it.
get a file descriptor on which a select() can be done for a live capture