RE: IFS Open Help...

Confusing? Perhaps.
But if you write a proc for general use, in RPG IV, you are (currently) limited
to 64k of data for parameters. With XML and the like, you may need to exceed
that limitation. So the address-of may be the way you access that data and pass
it to a subprocedure.
A field as the parameter could be used for 80 to 90% of the situations, but then
when the user needs to go beyond that, a pointer-to would be specified.
Therefore there doesn't need to be two versions of the same procedure. 

foo(szName);
foo(szData);
foo(szMy64kField);

 Qusptrus('QGPL/MYSTUFF' : ptrVar : apiErrorDS);
 foo(ptrVar : nDataLen);

The second parm could be optional unless a pointer is passed in.


-Bob Cozzi
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-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On
Behalf Of Scott Klement
Sent: Friday, March 09, 2007 1:42 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: IFS Open Help...

Hi Bob,

Qusptrus('QGPL/MYSTUFF' : pData : apiErrorDS); 
foo(pData : 1000000);

This passes the address of the data in the user space, and tells the
subproc that it is 1 megabyte in size. No conversion is performed and
the pointer to that data is passed to the foo() subprocedure.

I completely disagree. Your code uses a separate parameter (the length 
parameter) to dictate the length of the string.   It does not use a 
null-terminator, and therefore should not be coded with options(*String).

Just code it as a normal pointer.  When you want to pass a variable 
directly, use %ADDR().  When you want to write data from a pointer (such 
as your user space example) then pass the pointer directly.  It's much 
easier to read and understand, and doesn't confuse people who then start 
thinking that options(*string) requires %addr().