float8_in float8_out hash_bytes_uint32 hash_bytes_uint32_extended int4_in int4_out int8_in int8_out INTERVAL_IS_NOBEGIN INTERVAL_IS_NOEND interval_negate INTERVAL_NOBEGIN INTERVAL_NOEND INTERVAL_NOT_FINITE pg_datan pg_datan2 pg_dcos pg_dsin pg_hashfloat8 pg_hashfloat8extended pg_hashint8 pg_hashint8extended pg_hashtext pg_hashtextextended pg_interval_justify_hours

interval_negate() Interval * interval_negate ( const Interval *  interval ) Negate an interval. Note The PostgreSQL function interval_um_internal is declared static