Re: comprehensive info for ile rpg

["Larry Ducie" <Larry_Ducie@xxxxxxxxxxx>]

Hi Jim,
 
<snip>
 
Here's a tip - put this into a copybook called e.g. PGMSDS:
      /IF NOT DEFINED(PGMSDS)
      /DEFINE PGMSDS
      *
      * Program Status Data Structure
      *
     D PgmSDS         SDS
     D  PSDSMainProc                 10A
     D  PSDSStatus                    5S 0
     D  PSDSPrvSts                    5S 0
     D  PSDSStmt                      8A
     D  PSDSRoutine                   8A
     D  PSDSParms                     3S 0
     D  PSDSExcpMsg                   7A
     D   PSDSExcpTyp                  3A   Overlay(PSDSExcpMsg:1)
     D   PSDSExcpNbr                  4A   Overlay(PSDSExcpMsg:4)
     D                                4A
     D  PSDSWorkArea                 30A
</snip>
 
Although it probably doesn't make much difference to most programs these
days - remember that (almost) everything in the PSDS after the first 80
bytes is external to the object, and is expensive to retrieve if you never
need to use it.
 
The Websphere Development Studio ILE RPG Reference states: Call performance
with LR on will be greatly improved by having no PSDS, or a PSDS no longer
than 80 bytes, since some of the information to fill the PSDS after 80 bytes
is costly to obtain.
 
So, putting a full PSDS into every program may cause some unecessary
processing. It may never be noticible, but it is there. :-)
 
Cheers
 
Larry Ducie