clearAllCache() — clears the entire template cache
void clearAllCache(int expire_time);
As an optional parameter, you can supply a minimum age in seconds the cache files must be before they will get cleared.
Since Smarty version 3.1.14 it is possible to delete cache files by their individual expiration time at creation by passing constant SMARTY::CLEAR_EXPIRED as
Example 171. clearAllCache
// clear the entire cache
// clears all files over one hour old