How can you tell if a value is not numeric in Oracle?

Question

I have the following code that returns an error message if my value is invalid. I would like to give the same error message if the value given is not numeric.

Answer 1

CREATE OR REPLACE FUNCTION IS_NUMERIC(P_INPUT IN VARCHAR2) RETURN INTEGER IS
  RESULT INTEGER;
  NUM NUMBER ;
BEGIN
  NUM:=TO_NUMBER(P_INPUT);
  RETURN 1;
EXCEPTION WHEN OTHERS THEN
  RETURN 0;
END IS_NUMERIC;
/