extern int filter_n[FILTER_VARIABLE_COUNT]; /* filter variables */
extern BOOL filter_running; /* TRUE while running a filter */
extern int filter_sn[FILTER_VARIABLE_COUNT]; /* variables set by system filter */
extern int filter_n[FILTER_VARIABLE_COUNT]; /* filter variables */
extern BOOL filter_running; /* TRUE while running a filter */
extern int filter_sn[FILTER_VARIABLE_COUNT]; /* variables set by system filter */