Re: Calling similiar (overloaded) procedure that has *nopass *omit in the parameter

Hey Rory,
<snip>
If a procedure has a parameter passed to it as *OMIT, then the address of
that parameter is null. If this parameter is referenced (including simply
passing it to another procedure), could that cause runtime problems?
</snip>

Passing a null (or invalid) address of an incoming parameter to another procedure is the main cause of issues when using OPTIONS(*NOPASS) in chains of procedure calls, and is core to the OPs original problem. It is way too easy to pass a reference to a parm you didn't actually receive to another procedure. That is why we have to check %parms and use the appropriate call - ensuring we don't pass what we didn't receive.
This is not the same for OPTIONS(*OMIT). We did receive a valid (null) address. This null address can be safely passed on only if the procedure you are passing the ommitted parameter to also has OPTIONS(*OMIT) defined for that parameter. If it does the called procedure would have code checking the validity of the parameter.

<snip>
I assumed (there I go again, making an ass...) that using that parameter
directly could give the same sort of problems as referencing an unpassed
parameter (even though they are very different things).
</snip>

Using an incoming parameter on a call does not check the validity of the parameter address. It is just passed I believe. There will be scenarios where a conversion due to the use of const or value fails, but that is another issue.

<snip>
Essentially, all parameters are based variables and an omitted parameter is
simply one where the basing pointer is null. Thus my concern over passing an
omitted parameter to another procedure...
</snip>

I understand your concerns, but this would only be an issue if the procedure you are calling is not expecting an omitted parm. In this scenario you are correct. In the case of the OPs example both procedures had the same definition for parms 2 and 3. So, if proc1 accepts a *OMIT in parm 2 it is reasonable to pass that *OMIT along to parm 2 of proc2. Passing an invalid (or even sometimes accidentally valid) address for an non-passed parm 3 to proc2 is, however, totally unacceptable. This is why we check %parms and only pass parm 3 if %parms >= 3.

Cheers

Larry Ducie