Optional Parameters in Subprocedures

["Jon Paris" <Jon.Paris@xxxxxxxxxxxxxx>]

 >> If you are using the %addr, then why bother with the %parms?

Because there is nothing to say that there is not a null pointer (or data
that will test as a null pointer) already on the stack just waiting for the
unwary!!  Even worse (and I've seen the really nasty effect of this one)
there may be a perfectly _valid_ pointer on the stack.  It wasn't passed and
has nothing to do with the current call but if data gets moved to that field
good luck in tracking down the error!!

You should only check the %addr of a parameter you _know_ to have been
passed - hence the use of %parms

Jon Paris
Partner400