NL041: Parameter Data Area data structure violations

Description

Imaging a PDA named PDANAME, the data structure is expected to be as follows:

1 PDANAME /* (only 1 level 1)
2 PDANAME-IN /* (groups for input, output and optionally input/output)
3 ....
2 PDANAME-OUT
3 ....

Optionally PDANAME-INOUT can be a group too - it can even be standalone, if all your parameters are input/output (rare).

A PDA structure should follow these rules in order to be able to access each area individually through RESET and MOVE BY NAME statements:

RESET PDANAME.PDANAME-OUT
MOVE BY NAME other-structure TO PDANAME.PDANAME-IN

and to mention the fewest parameters in CALLNAT’s/PERFORM’s, while at the same time making a clear reference to the PDA in use, which improves readability:

CALLNAT 'SUBPGM' USING PDANAME
PERFORM EXTERNAL-SUBROUTINE-NAME PDANAME

If you have array groups, these are only possible at levels > 2.

This behavior can be configured using the natls.style.in_out_groups option in the analyzer configuration