How to check program is running or not

Question

Hi,
Is it possible to check whether a program is running or not?
I know when you try to compile a package which is running, oracle does not allow you compile it, it hangs. That is, somehow, Oracle knows the program is running. How can we check this information?
Suppose procedure below. If i ran it in one session, how can check that procedure p is running in other session?
I searched the forum. There is one( checking if a package procedure is already running ) thread but noone has replied.
Thanks....
SQL> DROP TABLE T;
Table dropped
SQL> CREATE TABLE T AS SELECT DUMMY D FROM DUAL;
Table created
SQL> CREATE OR REPLACE PROCEDURE p IS
  2    s VARCHAR2(12);
  3  BEGIN
  4    SELECT d INTO s FROM t;
  5    LOOP
  6      EXIT WHEN s = 'Y';
  7      SELECT d INTO s FROM t;
  8    END LOOP;
  9  END p;
10  /
Procedure created
SQL> exec p;

Answer 1

I found the answer from another thread.( Package Compilation Hangs )
Answer is : http://www.ixora.com.au/scripts/sql/executing_packages.sql