Points well taken, marios. Will try and fix strcpy(). Should certainly mention kqueue(), too. Will fix. Thanks.
https://man.openbsd.org/FreeBSD-11.1/sendfile.2 https://linux.die.net/man/2/sendfile
OpenBSD:
$ man 2 sendfile
man: No entry for sendfile in section 2 of the manual.
$ grep -rni sendfile /usr/include | wc -l
0
FreeBSD: # grep -rni sendfile /usr/include | wc -l
30
edit: typo