In the OpenWrt documentation for procd (see https://openwrt.org/docs/guide-developer/procd-init-scripts), the example script for procd respawn is shown as the following.
# respawn automatically if something died, be careful if you have an alternative process supervisor
# if process dies sooner than respawn_threshold, it is considered crashed and after 5 retries the service is stopped
procd_set_param respawn ${respawn_threshold:-3600} ${respawn_timeout:-5} ${respawn_retry:-5}
Later on the same page, the respawn description is listed as
A series of three consecutive numbers which set the respawn threshold, the respawn timeout and the respawn retry respectively. The timeout specifies the amount of seconds to wait before a service restart attempt, the retry value controls how many restart attempts will be made before a service is considered crashed and the threshold value in seconds controls the time frame in which the restart attempts are counted towards the retry limit. For example a threshold of 300 with a retry value of 10 will cause procd to consider the service to be crashed if the associated UNIX process terminated more than 10 times within a time frame of 5 minutes. No further restart attempts will be made for such crashed services unless an explicit restart is performed. Setting the retry value to 0 will cause procd to try restarting the service indefinitely. The default value for respawn is 3600 5 5.
My question is why the sample init script is specifying the respawn parameters as negative values.
Thanks.