Take and use at your own risk (StkTrc.zip). This is not sufficiently tested anywhere but under V5R1.

Three source members:

qclsrc.xrtnclrinf  -- X-ReturnCallerInfo
                      Can be compiled/used as *PGM or as bound proc.
qclsrc.tstpstktrc  -- Test calling stack trace as *PGM.
qclsrc.tstcstktrc  -- Test calling stack trace as bound procedure.

Calling XRTNCLRINF returns four parm values:

Lib  -- Library of caller
Pgm  -- Program name of caller
Mod  -- Module containing calling procedure
Prc  -- Procedure name of caller

An optional 5th parm is a logical variable:

'1'  -- Return values for calling *PGM
'0'  -- Return values for calling proc -- This is the default.

May be called by OPM or ILE *PGMs.