Clear dmesg in Freebsd

My environment: Freebsd 9.2

root@freebsd91:/root # sysctl kern.msgbuf_clear=1

kern.msgbuf_clear: 0 -> 0

root@freebsd91:/root # dmesg

root@freebsd91:/root #

Last updated on Jan 6th, 2014 by Sam Lin <samlin35@gmail.com>