Provided by:
freebsd-manpages_6.2-1_all 
NAME
watchdog - hardware and software watchdog
SYNOPSIS
options CPU_ELAN
options CPU_GEODE
options SW_WATCHDOG
#include <sys/watchdog.h>
DESCRIPTION
The watchdog facility is used for controlling hardware and software
watchdogs.
The interface is through a device /dev/fido which responds to a single
ioctl(2) call, WDIOCPATPAT.
The call takes a single argument which represents a timeout value
specified as an integer power of two nanoseconds.
The WD_ACTIVE flag signals that the watchdog will be kept from timing out
from userland, for instance by the watchdogd(8) daemon.
To disable the watchdogs, an argument of zero should be used.
The ioctl(2) call will return success if just one of the available
watchdog(9) implementations support the request. If the call fails, for
instance if none of watchdog(9) implementations support the timeout
length, all watchdogs are disabled and must be explicitly re-enabled.
EXAMPLES
u_int u = WD_ACTIVE | WD_TO_8SEC;
int fd = open("/dev/fido", O_RDWR);
ioctl(fd, WDIOCPATPAT, &u);
SEE ALSO
watchdogd(8), watchdog(9)
HISTORY
The watchdog code first appeared in FreeBSD 5.1.
AUTHORS
The watchdog facility was written by Poul-Henning Kamp 〈phk@FreeBSD.org〉.
The software watchdog code and this manual page were written by Sean
Kelly 〈smkelly@FreeBSD.org〉. Some contributions were made by Jeff
Roberson 〈jeff@FreeBSD.org〉.