bool_in bool_out pg_date_in pg_date_out pg_interval_cmp pg_interval_in pg_interval_make pg_interval_mul pg_interval_out pg_interval_pl pg_time_in pg_time_out pg_timestamp_in pg_timestamp_mi pg_timestamp_mi_interval pg_timestamp_out pg_timestamp_pl_interval pg_timestamptz_in pg_timestamptz_out

pg_interval_out() char * pg_interval_out ( const Interval *  span ) Convert a time span to external form. Note PostgreSQL function: Datum interval_out(PG_FUNCTION_ARGS)