Full NULL support

IBM does not intend to provide a solution to this request at this time, so it is being declined.

Note that some aspects of this requirement are already available.

There are two aspects in this requirement that are not already available:
- The ability to return a null-value from a procedure
- The ability to pass *NULL for a null-capable parameter
These aspects of the requirement are being declined. While these features would be very useful for RPG programmers, this team has quite a long list of higher priority requirements, so these features are not likely to be implemented anytime soon.

Here are the aspects the requirement that are already available as of version 7.3 of the ILE RPG compiler, if Control keyword ALWNULL(*USRCTL) is specified:
- Any variable can be defined with the NULLIND keyword
- You can specify a parameter for the NULLIND keyword to associate your own indicator as the null indicator for a field
- You can specify the *NULL option for EXTNAME or LIKEREC to define a externally-described data structure where all subfields have type indicator. You can then associate this data structure as the null indicators for an ordinary externally described data structure using the NULLIND keyword
- You can specify OPTIONS(*NULLIND) for a parameter. With this option, you can access the null indicator for the parameter.

Documentation:
- NULLIND keyword: https://www.ibm.com/docs/en/ssw_ibm_i_75/rzasd/dkwnullind.htm
- OPTIONS(*NULLIND): https://www.ibm.com/docs/en/ssw_ibm_i_75/rzasd/doptns.htm#doptns__nullind

IBM Power Systems Development

The CAAC has reviewed this requirement and recommends that IBM view this as a medium priority requirement that should be addressed. Expanding on the handling of NULL can always be improved.

Background: The COMMON Americas Advisory Council (CAAC) members have a broad range of experience in working with small and medium-sized IBM i customers. CAAC has a key role in working with IBM i development to help assess the value and impact of individual RFEs on the broader IBM i community, and has therefore reviewed your RFE.

For more information about CAAC, see www.common.org/caac

For more details about CAAC's role with RFEs, see http://www.ibmsystemsmag.com/Blogs/i-Can/May-2017/COMMON-Americas-Advisory-Council-%28CAAC%29-and-RFEs/

Nancy Uthke-Schmucki - CAAC Program Manager

This request is still a candidate to be an enhancement for the RPG compiler.

IBM will use this request as input to planning but no commitment is made or implied. This request will be updated in the future if IBM implements it. IBM will use votes and comments from others in the community to help prioritize this request.

Regarding the first example in the Use Case, by coding OPTIONS(*NULLIND) on the prototyped parameter, the procedure will be able to access and change %NULLIND for the parameter.

The following program demonstrates how OPTIONS(*NULLIND) works. I took advantage of a new 7.3 feature where you can define your own null-capable fields using the NULLIND keyword, but a similar program would work in any release starting with v5r4 if you had a field which was null-capable due to an externally-described file or data structure.

ctl-opt alwnull(*usrctl);

dcl-s fld char(1) inz('a') nullind;

%nullind(fld) = *off;
proc (fld : '1');
dsply ('after call, nullind is now ' + %nullind(fld));
return;

dcl-proc proc;
dcl-pi *n;
parm char(1) options(*nullind);
new_nullind ind const;
end-pi;
dsply ('in proc: nullind is ' + %nullind(parm));
%nullind(parm) = new_nullind;
return;
end-proc;

DSPLY in proc: nullind is 0
DSPLY after call, nullind is now 1

IBM has received the requirement and is evaluating it. IBM will provide a response after evaluation is complete.

Creating a new RFE based on Community RFE #90098 in product IBM i.