SD\_WATCHDOG\_ENABLED(3) sd\_watchdog\_enabled SD\_WATCHDOG\_ENABLED(3) .SH "NAME" sd\_watchdog\_enabled - Check whether the service manager expects watchdog keep-alive notifications from a service .SH "SYNOPSIS" ``` #include ``` .HP 576u **int sd\_watchdog\_enabled(int unset\_environment, uint64\_t \*usec);** .SH "DESCRIPTION" .PP **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. .PP 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)](/man/os/systemd/sd_notify.3) with a message string of WATCHDOG=1. .PP 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 zero. .PP If the *usec* parameter is non-**NULL**, **sd\_watchdog\_enabled()** will write the timeout in μs for the watchdog logic to it. .PP To enable service supervision with the watchdog logic, use *WatchdogSec=* in service files. See [**systemd.service**(5)](/man/os/systemd/systemd.service.5) for details. .PP Use [**sd\_event\_set\_watchdog**(3)](/man/os/systemd/sd_event_set_watchdog.3) to enable automatic watchdog support in [**sd-event**(3)](/man/os/systemd/sd-event.3)-based event loops. .SH "RETURN VALUE" .PP 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. .SH "NOTES" .PP Functions described here are available as a shared library, which can be compiled against and linked to with the **libsystemd** [**pkg-config**(1)](/man/os/systemd/pkg-config.1) file. .PP The code described here uses [**getenv**(3)](/man/os/systemd/getenv.3), which is declared to be not multi-thread-safe. This means that the code calling the functions described here must not call [**setenv**(3)](/man/os/systemd/setenv.3) from a parallel thread. It is recommended to only do calls to **setenv()** from an early phase of the program when no other threads have been started. .PP Internally, this function parses the *$WATCHDOG\_PID* and *$WATCHDOG\_USEC* environment variable. The call will ignore these variables if *$WATCHDOG\_PID* does not contain the PID of the current process, under the assumption that in that case, the variables were set for a different process further up the process tree. .SH "ENVIRONMENT" .PP *$WATCHDOG\_PID* 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. Added in version 209. .RE .PP *$WATCHDOG\_USEC* 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. Added in version 209. .RE .SH "HISTORY" .PP **sd\_watchdog\_enabled()** was added in version 209. .SH "SEE ALSO" .PP [**systemd**(1)](/man/os/systemd/systemd.1), [**sd-daemon**(3)](/man/os/systemd/sd-daemon.3), [**daemon**(7)](/man/os/systemd/daemon.7), [**systemd.service**(5)](/man/os/systemd/systemd.service.5), [**sd\_notify**(3)](/man/os/systemd/sd_notify.3), [**sd\_event\_set\_watchdog**(3)](/man/os/systemd/sd_event_set_watchdog.3) systemd 262.2 --- Document: sd_watchdog_enabled(3) from systemd 262.2-r1 (Chainguard OS) Source: https://github.com/systemd/systemd