add_date_int add_interval_interval add_timestamptz_interval AdjustIntervalForTypmod bool_in bool_out bstring2bytea cstring2text date2timestamp date2timestamp_opt_overflow date2timestamptz_opt_overflow date_in date_out date_to_timestamp date_to_timestamptz datum_initcap datum_lower datum_textcat datum_upper float8_in float8_in_opt_error float8_out int4_in int4_out int8_in int8_out interval_cmp interval_cmp_value interval_in interval_make interval_negate interval_out interval_sign MAXINT4LEN MAXINT8LEN MEOSAdjustTimeForTypmod MEOSAdjustTimestampForTypmod MEOSAdjustTimestampForTypmodError minus_date_date minus_date_int minus_timestamptz_interval minus_timestamptz_timestamptz mul_interval_double parse_bool_with_len pg_datan pg_datan2 pg_date_in pg_date_out pg_dcos pg_dsin pg_hashfloat8 pg_hashfloat8extended pg_hashint8 pg_hashint8extended pg_hashtext pg_hashtextextended pg_interval_cmp pg_interval_in pg_interval_justify_hours pg_interval_out pg_lltoa pg_ltoa pg_strtoint32 pg_strtoint64 pg_timestamp_in pg_timestamp_out pg_timestamptz_in pg_timestamptz_out pg_ulltoa_n pg_ultoa_n pnstrdup SAMESIGN text2cstring text_cmp text_copy text_initcap text_lower text_upper textcat_text_text time_in time_out timestamp_in timestamp_in_common timestamp_out timestamp_out_common timestamp_to_date timestamptz_in timestamptz_out timestamptz_to_date varstr_cmp

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