Re: Pointer / Based issue

"Ellsberry, Steve" wrote:
> ...
> In the service program I have the procedure interface defined as
> p  ErrorsInDS                 pi                   n
>        PointerPassedIn                            *
> 
> I also have a data structure in the procedure defined as
> d FeatTypeDS                ds             Qualified
> Based(PointerPassedIn)
> d   dsFeat                                3     dim(1000)
> d   dsType                               2     dim(1000)
> ...
> The DS is the service program contains all
> asterisks.
> 

Steve, the problem you are seeing is due to a limitation of the
debugger.  It can't evaluate any variable that is based on a pointer
that is itself based. (A parameter passed by reference is considered
"based" on the address of the passed parameter.)

Good advice: Do what Scott suggested and code the procedure to pass the
data structure by reference instead of passing its address.

Bad advice: You _could_ solve the debug problem by copying the pointer
to a local pointer, and basing your data structure on the local
pointer.  Or by passing the parameter by value.


But in some cases it's unavoidable to have based-on-based situations. 
The RPG debugger uses the -> syntax to get around the problem:

  ===> EVAL PointerPassedIn->FeatTypeDS
or 
  ===> EVAL PointerPassedIn->dsFeat
  ===> EVAL PointerPassedIn->dsType

If the DS also had a pointer subfield dsPtr, and some other field say
fldx was based on that pointer, you could do
  ===> EVAL PointerPassedIn->dsPtr->fldx
etc.