SD_WATCHDOG_ENABLED(3)         sd_watchdog_enabled        SD_WATCHDOG_ENABLED(3)

       sd_watchdog_enabled - Check whether the service manager expects watchdog
       keep-alive notifications from a service

       #include <systemd/sd-daemon.h>

       int sd_watchdog_enabled(int unset_environment, uint64_t *usec);

       sd_watchdog_enabled() may be called by a service to detect whether the
       service manager expects regular keep-alive watchdog notification events
       from it, and the timeout after which the manager will act on the service
       if it did not get such a notification.

       If the $WATCHDOG_USEC environment variable is set, and the $WATCHDOG_PID
       variable is unset or set to the PID of the current process, the service
       manager expects notifications from this process. The manager will usually
       terminate a service when it does not get a notification message within
       the specified time after startup and after each previous message. It is
       recommended that a daemon sends a keep-alive notification message to the
       service manager every half of the time returned here. Notification
       messages may be sent with sd_notify(3) with a message string of

       If the unset_environment parameter is non-zero, sd_watchdog_enabled()
       will unset the $WATCHDOG_USEC and $WATCHDOG_PID environment variables
       before returning (regardless of whether the function call itself
       succeeded or not). Those variables are no longer inherited by child
       processes. Further calls to sd_watchdog_enabled() will also return with

       If the usec parameter is non-NULL, sd_watchdog_enabled() will write the
       timeout in µs for the watchdog logic to it.

       To enable service supervision with the watchdog logic, use WatchdogSec=
       in service files. See systemd.service(5) for details.

       Use sd_event_set_watchdog(3) to enable automatic watchdog support in sd-
       event(3)-based event loops.

       On failure, this call returns a negative errno-style error code. If the
       service manager expects watchdog keep-alive notification messages to be
       sent, > 0 is returned, otherwise 0 is returned. Only if the return value
       is > 0, the usec parameter is valid after the call.

       These APIs are implemented as a shared library, which can be compiled and
       linked to with the libsystemd pkg-config(1) file.

       Internally, this function parses the $WATCHDOG_PID and $WATCHDOG_USEC
       environment variable. The call will ignore these variables if
       $WATCHDOG_PID does not contain the PID of the current process, under the
       assumption that in that case, the variables were set for a different
       process further up the process tree.

           Set by the system manager for supervised process for which watchdog
           support is enabled, and contains the PID of that process. See above
           for details.

           Set by the system manager for supervised process for which watchdog
           support is enabled, and contains the watchdog timeout in µs. See
           above for details.

       systemd(1), sd-daemon(3), daemon(7), systemd.service(5), sd_notify(3),

systemd 247                                               SD_WATCHDOG_ENABLED(3)