i need to access some connection unique identifier from SQL.

In "Control Center" i stumbled into "Application" where i connection id's of
the form:
GA00000B.FC12.00BAC2202852
GA000010.P10C.00E582202330
GA00000B.I212.00D402201110
*LOCAL.DB2.060302193817
*LOCAL.DB2.060302193816
GA00012.K806.012A02162441

i've tried random SQL constructs such as

SELECT connection
SELECT current connection
SELECT current_connection
SELECT connection;
SELECT current connection;
SELECT current_connection;
SELECT connection$
SELECT current connection$
SELECT current_connection$
SELECT connection FROM MyTable
SELECT connection FROM MyTable;
SELECT spid
SELECT spid;
SELECT current spid
SELECT sp_id
SELECT CLIENT ACCTNG
SELECT CLIENT ACCTNG;
SELECT CLIENT ACCTNG$
SELECT CLIENT ACCTNG
SELECT CURRENT CLIENT ACCTNG
SELECT CLIENT_ACCTNG
SELECT CURRENT CLIENT_ACCTNG

None work.

What i am really looking for is a place to store per-connection data (a
software user id), but i cannot see any programatic access to any such
"session variable" / "context info". i need this information, because i am
trying to implement trigger based audit logging, and i need to know the user
of the software who is making the changes.

In the absence of a system provided "session information" store, i will have
to maintain my own table of "Connection ID <--> User ID" mappings.

Any ideas on any of the above?