Re: Program design to minimize record locks

["Gene Burns" <burns.gene@xxxxxxxxx>]

Using the following format will put the data in the DS on the chain or read.

D  FileNameDS     e ds        extname(Filename)


gene

On 7/19/07, Pete Helgren <Pete@xxxxxxxxxx> wrote:
> OK! So the compile works but the I am not getting what I expected (maybe
> this IS harder than I thought).
>
> Based on the prior posts from Booth, I thought I understood that the D
> spec for the data structure would hold a copy of the data read from the
> file "automagically".  He said "The FileNameDS does in fact always have
> the most recently read data values, whether from the original read(n),
> the screen exfmt, or the locking read."  So either I misunderstood or I
> am doing something wrong (that wouldn't surprise me).
>
> Booth suggested the following:
>
> D  FileNameDS      ds        extname(Filename)
> D  OrigData        s         like(FileNameDS)
> D  NewData         s         like(FileNameDS)
>
>
>
> This wouldn't compile until I changed the extname to likerec (and I had
> to add an "e" for externally described). I assumed that a read on
> Filename would automatically populate FileNameDS but that isn't the
> case.  A read on Filename puts no data into FileNameDS. So I
> misunderstood or did it wrong.
>
> Pete
>
>
> Pete Helgren wrote:
> > Got it! I appreciate the clarification. It compiles now.
> >
> > Thanks,
> >
> > Pete
> >
> >
> > Scott Klement wrote:
> >
> >> Pete Helgren wrote:
> >>
> >>
> >>> A little wrinkle here:
> >>> The compiler seems unhappy with the fact that I have the RENAME
> >>>
> >>> File spec has:
> >>>
> >>> FPMYFILE   UF A E           K DISK    RENAME(FMYFILE:FILE01)
> >>> DFileNameDS     E ds                  extname(FILE01)
> >>>
> >>>
> >> Did you mean to use LIKEREC?
> >>
> >> A data structure defined with EXTNAME has absolutely no relationship
> >> with the F-spec.  Instead, you tell EXTNAME the external name of a
> file,
> >> and it looks for it on disk to get the fields.   Since the argument for
> >> EXTNAME is a FILE NAME (not a record format name) and it's looking
> >> directly at the file (not at the F-spec) I wonder if you really meant
> to
> >> use LIKEREC?
> >>
> >> LIKEREC defines a structure to be like a record format that you've
> >> defined on an F-spec.  So you could say
> >>
> >>     DFileNameDs       ds                  likerec(FILE01:*input)
> >>
> >> And that would work, because it's argument is the RECORD FORMAT NAME
> >> (which is what you renamed) and it's looking at your F-spec rather than
> >> directly looking at the file.
> >>
> >>
> >>
> --
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