Re: SetLL *start

[CRPence <CRPbottle@xxxxxxxxx>]

On 2/27/11 2:08 PM, M. Lazarus wrote:
> Is there any good technical (not historical) reason that we still
> have any opcodes that can't use record formats and file names, for
> data files, interchangeably?  PF's can't contain multiple formats.
> Multi-format LF's are relatively rare nowadays.  The only time it
> would require differentiation is if a MFLF is used.
>
> Is there a consideration to relax that requirement?

  Just some thoughts which may or may not be relevant to that request, 
so FWiW...

  Overrides of a database file to another file [with multiple formats], 
even to a device file may be an issue.  The RPG language operates over 
the Common Data Management for accessing Database and Device files, 
versus defining the rules of data management.  The record format is 
/common/ across the file types, and thus the RcdFmt is reflected in the 
Common Data Management interface to the database file, just as to the 
various device file types.  Consider that DSPFD of a Save File [device 
file attribute SAVF] shows that the file has a format which is defined 
in the ODP even though no actual internal *FMT object type exists; if 
any extended type attribute of the *FILE object type had no use for a 
format, that is surely one, but for reading and writing, the common DM 
requires the format to be /common/ across the various file types.

  The data management and database support multiple formats for a PF 
via "redirection" to an external format; I know only of IDDU in this 
capacity.  I am not aware if there is any support via RPG for that 
capability; i.e. access to a program-described file as though the file 
were externally described, via redirection to the file and record format 
definitions in the IDDU [*DTADCT] data dictionary.  To the common data 
management the difference between MFLF and MFPF is minor; i.e. they 
operate effectively the same, in how the request is handed off to the 
database, where both require a format name [though possibly defaulting 
to *FIRST if unspecified] to operate properly.

  Some interfaces such as OPNQRYF offer a special value *ONLY for the 
RcdFmt such that a file being acted on, for which more than one format 
exists, an error will be issued; e.g. CPD3104 for the FILE parameter.

Regards, Chuck