Re: Address of Variable in Service Program Exported Procedure

On Nov 7, 2022, at 4:11 PM, Vinay Gavankar <vinaygav@xxxxxxxxx> wrote:

There is more than one value being returned, hence passing it as a parameter

On Mon, Nov 7, 2022 at 4:00 PM Charles Wilt <charles.wilt@xxxxxxxxx> wrote:

for readability, you can still RETURN such a large results..

Just use the RTNPARM keyword on the procedure...

Behind the scenes, RPG will actually pass it as an additional parm.

Charles


On Mon, Nov 7, 2022 at 1:48 PM Vinay Gavankar <vinaygav@xxxxxxxxx> wrote:

The reason it was being done was the variable is 32K bytes. I guess it
shouldn't matter as RPG would internally pass the pointer, so there would
be no effect on program performance.

On Mon, Nov 7, 2022 at 3:43 PM Vinay Gavankar <vinaygav@xxxxxxxxx>

wrote:

Thanks everyone for your replies. I have changed the Service program

and

the calling programs to use variables instead of pointers.

On Mon, Nov 7, 2022 at 12:24 PM Jon Paris <jon.paris@xxxxxxxxxxxxxx>
wrote:

As others have intimated this is a _really_ bad idea even if it

worked -

which would be circumstance dependent. It is a very error prone

design.

Returning a pointer in general is rarely a good idea for two main
reasons. One, the code that has the address can change the content of

the

variable "invisibly". And 2) The code that has that pointer has no way

of

knowing if it is still valid! If it pointed to stack storage (for

example)

it would still be valid pointer long after the storage had been reused

by

another process!

This is in the category of things your mother (had she been a

programmer)

would have warned you would make you go blind if you kept doing it!


Jon P.

On Nov 7, 2022, at 9:52 AM, Vinay Gavankar <vinaygav@xxxxxxxxx>

wrote:

Hi,

We have an exported procedure in a Service program (RPG) which needs

to

pass back the address of a variable, so that the calling program can
use the value in that variable.

Can the calling program (RPG) access the value of the variable if it

is

defined within that exportable procedure, or does the variable need

to

be

'global' in the Service Program?

TIA
Vinay
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