Finding Actual Field Length of Parms for QCMDEXC

I don't mean to whip a dead horse, but I haven't found a solution for this one. 
 At least, not an answer that I'm satisfied with.  I know this question has 
been solved on the RPGIV threads.

How do you know the actual length of parameters passed for call to QCMDEXC 
within a CL program?  I'm trying to modify an old Midrange Computing program 
that has a "Wait R U Sure?"  question for those critical update programs to 
stop users from running inadvertently.

I want to add the ability to pass parms to it.  The PARM is defined as TYPE(*X) 
on the command.  I have &QPARM defined as *CHAR with a length of 1282 (32 chars 
per parm X 40 parms).  This however won't work because the TYPE(*X) varies in 
length.

Any ideas?