The watchdog concept

The watchdog concept of the audiomanger is based on systemd. When systemd is configured via the unit file to use a watchdog and watchdog support is activated in the audiomanager, the audiomanager will reset the watchdog via the mainloop in the given interval to prevent systemd from restarting the audiomanager.
If the audiomanager is stuck for whatever reason, systemd will not get this update and restart the audiomanager.

Watchdog configuration

By default, the watchdog is enabled in the audiomanager, you can disable the watchdog functionality by setting the cmake build option "WITH_SYSTEMD_WATCHDOG" to OFF, either by modifying the cmake cache with ccache or by passing -DWITH_SYSTEMD_WATCHDOG=OFF to cmake.
The interval for checking the watchdog can be set in the unitfile of systemd by setting "WatchdogSec". The other settings need to be done as well:

Restart=always
WatchdogSec=2
NotifyAccess=main

The intervall for pinging systemd is set to the half of "WatchdogSec".

Integration with systemd

The audiomanager will use the library proviced by "libsystemd-daemon" if it is available on the system. If this library is not available, the files sd-daemon.c and sd-daemon.h that are provided with the audiomanager and released under MIT licence by Lennard Poettering will be used to connect to systemd.

more information can be found here: am::CAmWatchdog and sd-daemon.h .