RE: Stacking data structures

["Bob Cozzi \(RPGIV\)" <cozzi@xxxxxxxxx>]

You can't take the address of a variable that also has the BASED keyword
specified. By definition, Based means that the variable has no storage.
That is, it is simply a viewport to the data at the location (what ever
location) that is specified in the based-on pointer variable.

You should create the biggest data structure you'll need, and then you
can assign that data structure's address to a pointer variable. The
other data structures can be BASED on that same pointer, but the pointer
should be set to the %ADDR of the biggest one.

Bob Cozzi
cozzi@rpgiv.com
Visit the new on-line iSeries Forums at: http://www.rpgiv.com/forum

> -----Original Message-----
> From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]
On
> Behalf Of rob@dekko.com
> Sent: Tuesday, September 18, 2001 10:28 AM
> To: rpg400-l@midrange.com
> Subject: Stacking data structures
>
>
> Because of the many possible formats you can use on some of the list
API's
> we thought of stacking data structures.  Below is a sample:
>
>       * OBJL0100 - QUSLOBJ - List Objects - Object names
>      D pOBJL0100       S               *   Inz(%addr(OBJL0100D))
> Ptr object list
>      D OBJL0100        DS                  Based(pOBJL0100)
>      D  OLObjNam                     10A
> Object name
>      D  OLObjLib                     10A
> Object library
>      D  OLObjTyp                     10A
> Object type
>
>       * OBJL0200 - QUSLOBJ - List Objects - Text description and
extended
> attribute
>      D pOBJL0200       S               *   Inz(%addr(OBJL0200D))
> Ptr object list
>      D OBJL0200        DS                  Based(pOBJL0200)
>      D  OBJL0100D                          Like(OBJL0100)
>      D  OLObjSts                      1A
> Object status
>      D  OLExtAtr                     10A
> Extended attribute
>      D  OLTxtDsc                     50A
> Text description
>      D  OLDefAtr                     10A
> User defined atr
>      D  OLRes1                        7A
> Reserved
>
>       * OBJL0300 - QUSLOBJ - List Objects - Basic object information
>      D pOBJL0300       S               *
>      D OBJL0300        DS                  Based(pOBJL0300)
>      D  OBJL0200D                          Like(OBJL0200)
>      D  OLAuxSP                      10I 0
> Aux storage pool
>      D  OLObjOwn                     10A
> Object owner
>      D  OLObjDom                      2A
> Object domain
>      D  OLCrtDat                      8A
> Create date/time
>      D  OLChgDat                      8A
> Change date/time
>      D  OLStorage                    10A
> Storage
>      D  OLCmprSts                     1A
> Compression status
>      D  OLAlwChg                      1A
> Allow program change
>      D  OLAudVal                     10A
> Auditing value
>      D  OLRes2                        9A
> Reserved
>
> But, when we compile this we get
>  Msg id  Sv Number Seq     Message text
> *RNF0314 20      7 000200+ Built-in function %ADDR(OBJL0100D) does not
have
> a value
>                            known at compile-time; built-in function is
> ignored.
> *RNF0314 20     14 000900+ Built-in function %ADDR(OBJL0200D) does not
have
> a value
>                            known at compile-time; built-in function is
> ignored.
>
> So we tried to cheat and changed a few lines:
>      D pOBJL0300       S               *
> became
>      D pOBJL0300       S               *   Inz(%addr(OBJL0300P))
> Ptr object list
> and we added
>      D OBJL0300P       S              1A
> and got the same results.
>
> I)  Should I try reporting this as a bug?
> II)  Any suggested workarounds?
>
>
> Rob Berendt
>
> ==================
> A smart person learns from their mistakes,
> but a wise person learns from OTHER peoples mistakes.
>
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