http_cache_last_modified Caching by last modification &reftitle.description; boolhttp_cache_last_modified inttimestamp_or_expires Attempts to cache the sent entity by its last modification date. If the supplied argument is greater than 0, it is handled as timestamp and will be sent as date of last modification. If it is 0 or omitted, the current time will be sent as Last-Modified date. If it's negative, it is handled as expiration time in seconds, which means that if the requested last modification date is not between the calculated timespan, the Last-Modified header is updated and the actual body will be sent. A log entry will be written to the cache log if the &link.http.configuration; http.log.cache is set and the cache attempt was successful. &reftitle.parameters; timestamp_or_expires Unix timestamp &reftitle.returnvalues; Returns FALSE on failure, or exits with 304 Not Modified if the entity is cached.