Re: Declaring the same DS in caller and callee

On 17/02/2009, at 4:58 AM, Vern Hamberg wrote:

I don't remember the circumstances, and it may have been in an earlier
release - I have run into the need to declare the pointer and/or to
initialize the pointer explicitly with the %addr() function. The syntax
you give below seems to work most of the time, however. As I say, I
don't remember where I've had the problem. But leaving out one or both
items resulted in an MCH3601.

You might want to rethink this. Both

D var S 10 BASED(@var)

and

D @var S *
D var S 10 BASED(@var)

will result in a NULL pointer named @var being declared and var will be based on that NULL pointer. If your code attempts to reference either the pointer or the based storage you will get MCH3601 (except for the obvious case of a reference that assigns an address to the pointer).

You must set the basing pointer to a valid address before referencing the based variable. Whether you do that by using INZ(%ADDR())--which obviously requires you to explicitly declare the basing pointer--or via an EVAL @var = %ADDR() operation is immaterial. This is true of all languages with pointer support (on iSeries). If the pointer is not set you will get MCH3601 when you attempt to reference storage based on that pointer.

Perhaps you were bitten by Barbara's earlier point that a global basing pointer will be overridden by a compiler-generated local basing pointer? If so, that's a different issue.

Regards,
Simon Coulter.
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