11g introduced two new views: V$SQLFN_METADATA and V$SQLFN_ARG_METADATA, which provide metadata for all Oracle SQL built-in operations and functions.
SQL> set linesize 2500 SQL> SELECT * FROM v$sqlfn_metadata where name = 'REGEXP_SUBSTR' ; FUNC_ID NAME MINARGS MAXARGS DATATYPE VERSION ANA AGG DISP_TYPE USAGE DESCR ---------- ------------------------------ ---------- ---------- -------- ------------ --- --- ------------- ------------------------------ ------------------------------ 526 REGEXP_SUBSTR 2 5 STRING V10 Oracle NO NO NORMAL SQL> SELECT * FROM v$sqlfn_arg_metadata WHERE func_id = 526 ; FUNC_ID ARGNUM DATATYPE DESCR ---------- ---------- -------- ------------------------------ 526 1 STRING 526 2 STRING 526 3 NUMERIC 526 4 NUMERIC 526 5 STRING
This new feature may help especially to third party tools to maintain the function usage metadata redundantly in the application layer. For more informations you may check the documentation and this oracle-developer.net article.