watchdog(4)

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>.

BSD June 25, 2003

BSD