This is the length of time in seconds that a template cache is valid. Once this time has expired, the cache will be regenerated.
$cachingmust be turned on (either 1 or 2) for
$cache_lifetimeto have any purpose.
$cache_lifetimevalue of -1 will force the cache to never expire.
A value of 0 will cause the cache to always regenerate (good for testing only, to disable caching a more efficient method is to set
enabled, the cache files will be regenerated every time, effectively
disabling caching. You can clear all the cache files with the
function, or individual cache files (or groups) with the